# 2010 United States Senate elections

The 2010 United States Senate elections were held on November 2, 2010, from among the United States Senate's 100 seats. A special election was held on January 19, 2010, for a midterm vacancy in Massachusetts. 34 of the November elections were for 6-year terms to the Senate's Class 3, while other 3 were special elections to finish incomplete terms. Those 37 November elections featured 19 incumbent Democrats (7 of whom retired or were defeated in the primary) and 18 incumbent Republicans (8 of whom retired or were defeated in the primary).
After the 2008 elections, the Senate was composed of 58 Democrats, 40 Republicans, and 2 independents who caucused with the Democrats. However, in a January 2010 special election, Republicans picked up a seat in Massachusetts thereby reducing Democrats' majority to 57 seats.
Republicans won 4 seats held by retiring Democrats and also defeated 2 incumbent Democrats, for a Republican net gain of 6 seats. This was the first time since 1994 that Republicans successfully defended all of their own seats. This was also the fourth consecutive election of Class 3 senators where Democrats failed to gain seats. Despite the Republican gains, the Democrats retained a majority of the Senate with 51 seats plus the 2 Independents who caucused with them, compared to the 47 Republican seats. As of 2025, this was the last time Republicans won U.S. Senate seats in Illinois and New Hampshire.

## Results summary

| 51 | 2 | 47 |
| Democratic | Independent | Republican |
Shading indicates party with largest share of that line. Does not include the January 2010 special election in Massachusetts.
| Parties | Parties | | | | | | | | Total |
| Parties | Parties | Democratic | Republican | Independent | Libertarian | Green | Constitution | Others | Total |
| Last elections (2008) Before the November elections | Last elections (2008) Before the November elections | 57 | 41 | 2 | — | — | — | — | 100 |
| Not Up | Total | 38 | 23 | 2 | — | — | — | — | 63 |
| Not Up | Class 1 (2006→2012) | 19 | 10 | 2 | — | — | — | — | 31 |
| Not Up | Class 2 (2008→2014) | 19 | 13 | — | — | — | — | — | 32 |
| Up | Total | 19 | 18 | — | — | — | — | — | 37 |
| Up | Class 1 | 2 | — | — | — | — | — | — | 2 |
| Up | Class 2 | 1 | — | — | — | — | — | — | 1 |
| Up | Class 3 | 16 | 18 | — | — | — | — | — | 34 |
| Incumbent retired | Total before | 6 | 6 | — | — | — | — | — | 12 |
| Incumbent retired | Held by same party | 3 | 6 | — | — | — | — | — | 9 |
| Incumbent retired | Replaced by other party | 3 Democrats replaced by 3 Republicans | 3 Democrats replaced by 3 Republicans | — | — | — | — | — | 3 |
| Incumbent retired | Result after | 3 | 9 | — | — | — | — | — | 12 |
| Incumbent ran | Total before | 13 | 12 | — | — | — | — | — | 25 |
| Incumbent ran | Won election | 10 | 10 | — | — | — | — | — | 20 |
| Incumbent ran | Lost re-election | 2 Democrats replaced by 2 Republicans | 2 Democrats replaced by 2 Republicans | — | — | — | — | — | 2 |
| Incumbent ran | Lost renomination but won re-election | — | 1 | — | — | — | — | — | 1 |
| Incumbent ran | Lost renomination but party held | — | 1 | — | — | — | — | — | 1 |
| Incumbent ran | Lost renomination and party lost | 1 Democrat replaced by 1 Republican | 1 Democrat replaced by 1 Republican | — | — | — | — | — | 1 |
| Incumbent ran | Result after | 10 | 15 | — | — | — | — | — | 25 |
| Total elected | Total elected | 13 | 24 | — | — | — | — | — | 37 |
| Net gain/loss | Net gain/loss | 6 | 6 | — | — | — | — | — | 6 |
| Nationwide vote | Votes | 32,405,787 | 34,616,463 | 155,846 | 776,327 | 552,006 | 178,860 | 3,100,833 | 71,786,122 |
| Nationwide vote | Share | 45.14% | 48.22% | 0.22% | 1.08% | 0.77% | 0.25% | 4.32% | 100% |
| Result | Result | 51 | 47 | 2 | — | — | — | — | 100 |
| End of this Congress | End of this Congress | 56 | 42 | 2 | — | — | — | — | 100 |
Source: Clerk of the U.S. House of Representatives

## Change in composition
### After the January special election

| D$_1$ | D$_2$ | D$_3$ | D$_4$ | D$_5$ | D$_6$ | D$_7$ | D$_8$ | D$_9$ | D$_{10}$ |
| D$_{20}$ | D$_{19}$ | D$_{18}$ | D$_{17}$ | D$_{16}$ | D$_{15}$ | D$_{14}$ | D$_{13}$ | D$_{12}$ | D$_{11}$ |
| D$_{21}$ | D$_{22}$ | D$_{23}$ | D$_{24}$ | D$_{25}$ | D$_{26}$ | D$_{27}$ | D$_{28}$ | D$_{29}$ | D$_{30}$ |
| D$_{40}$ | D$_{39}$ | D$_{38}$ | D$_{37}$ | D$_{36}$ | D$_{35}$ | D$_{34}$ | D$_{33}$ | D$_{32}$ | D$_{31}$ |
| D$_{41}$ | D$_{42}$ | D$_{43}$ | D$_{44}$ | D$_{45}$ | D$_{46}$ | D$_{47}$ | D$_{48}$ | D$_{49}$ | D$_{50}$ |
| Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | D$_{51}$ |
| R$_{41}$ Mass. (sp) Gain | I$_2$ | I$_1$ | D$_{57}$ | D$_{56}$ | D$_{55}$ | D$_{54}$ | D$_{53}$ | D$_{52}$ | D$_{51}$ |
| R$_{40}$ | R$_{39}$ | R$_{38}$ | R$_{37}$ | R$_{36}$ | R$_{35}$ | R$_{34}$ | R$_{33}$ | R$_{32}$ | R$_{31}$ |
| R$_{21}$ | R$_{22}$ | R$_{23}$ | R$_{24}$ | R$_{25}$ | R$_{26}$ | R$_{27}$ | R$_{28}$ | R$_{29}$ | R$_{30}$ |
| R$_{20}$ | R$_{19}$ | R$_{18}$ | R$_{17}$ | R$_{16}$ | R$_{15}$ | R$_{14}$ | R$_{13}$ | R$_{12}$ | R$_{11}$ |
| R$_1$ | R$_2$ | R$_3$ | R$_4$ | R$_5$ | R$_6$ | R$_7$ | R$_8$ | R$_9$ | R$_{10}$ |

### Before the November elections

| D$_1$ | D$_2$ | D$_3$ | D$_4$ | D$_5$ | D$_6$ | D$_7$ | D$_8$ | D$_9$ | D$_{10}$ |
| D$_{20}$ | D$_{19}$ | D$_{18}$ | D$_{17}$ | D$_{16}$ | D$_{15}$ | D$_{14}$ | D$_{13}$ | D$_{12}$ | D$_{11}$ |
| D$_{21}$ | D$_{22}$ | D$_{23}$ | D$_{24}$ | D$_{25}$ | D$_{26}$ | D$_{27}$ | D$_{28}$ | D$_{29}$ | D$_{30}$ |
| D$_{40}$ Calif. Ran | D$_{39}$ Ark. Ran | D$_{38}$ | D$_{37}$ | D$_{36}$ | D$_{35}$ | D$_{34}$ | D$_{33}$ | D$_{32}$ | D$_{31}$ |
| D$_{41}$ Colo. Ran | D$_{42}$ Conn. Retired | D$_{43}$ Del. (sp) Retired | D$_{44}$ Hawaii Ran | D$_{45}$ Ill. (reg) Ill. (sp) Retired | D$_{46}$ Ind. Retired | D$_{47}$ Md. Ran | D$_{48}$ Nev. Ran | D$_{49}$ N.Y. (reg) Ran | D$_{50}$ N.Y. (sp) Ran |
| Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | D$_{51}$ N.D. Retired |
| R$_{41}$ Utah Ran | I$_2$ | I$_1$ | D$_{57}$ Wis. Ran | D$_{56}$ W.Va. (sp) Retired | D$_{55}$ Wash. Ran | D$_{54}$ Vt. Ran | D$_{53}$ Pa. Ran | D$_{52}$ Ore. Ran | D$_{51}$ N.D. Retired |
| R$_{40}$ S.D. Ran | R$_{39}$ S.C. Ran | R$_{38}$ Okla. Ran | R$_{37}$ Ohio Retired | R$_{36}$ N.C. Ran | R$_{35}$ N.H. Retired | R$_{34}$ Mo. Retired | R$_{33}$ La. Ran | R$_{32}$ Ky. Retired | R$_{31}$ Kan. Retired |
| R$_{21}$ | R$_{22}$ | R$_{23}$ | R$_{24}$ Ala. Ran | R$_{25}$ Alaska Ran | R$_{26}$ Ariz. Ran | R$_{27}$ Fla. Retired | R$_{28}$ Ga. Ran | R$_{29}$ Idaho Ran | R$_{30}$ Iowa Ran |
| R$_{20}$ | R$_{19}$ | R$_{18}$ | R$_{17}$ | R$_{16}$ | R$_{15}$ | R$_{14}$ | R$_{13}$ | R$_{12}$ | R$_{11}$ |
| R$_1$ | R$_2$ | R$_3$ | R$_4$ | R$_5$ | R$_6$ | R$_7$ | R$_8$ | R$_9$ | R$_{10}$ |

### Result of the November elections

| D$_1$ | D$_2$ | D$_3$ | D$_4$ | D$_5$ | D$_6$ | D$_7$ | D$_8$ | D$_9$ | D$_{10}$ |
| D$_{20}$ | D$_{19}$ | D$_{18}$ | D$_{17}$ | D$_{16}$ | D$_{15}$ | D$_{14}$ | D$_{13}$ | D$_{12}$ | D$_{11}$ |
| D$_{21}$ | D$_{22}$ | D$_{23}$ | D$_{24}$ | D$_{25}$ | D$_{26}$ | D$_{27}$ | D$_{28}$ | D$_{29}$ | D$_{30}$ |
| D$_{40}$ Colo. Elected | D$_{39}$ Calif. Re-elected | D$_{38}$ | D$_{37}$ | D$_{36}$ | D$_{35}$ | D$_{34}$ | D$_{33}$ | D$_{32}$ | D$_{31}$ |
| D$_{41}$ Conn. Hold | D$_{42}$ Del. (sp) Hold | D$_{43}$ Hawaii Re-elected | D$_{44}$ Md. Re-elected | D$_{45}$ Nev. Re-elected | D$_{46}$ N.Y. (reg) Re-elected | D$_{47}$ N.Y. (sp) Elected | D$_{48}$ Ore. Re-elected | D$_{49}$ Vt. Re-elected | D$_{50}$ Wash. Re-elected |
| Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | Majority → | D$_{51}$ W.Va. (sp) Hold |
| R$_{41}$ Utah Hold | R$_{42}$ Ark. Gain | R$_{43}$ Ill. (reg) Ill. (sp) Gain | R$_{44}$ Ind. Gain | R$_{45}$ N.D. Gain | R$_{46}$ Pa. Gain | R$_{47}$ Wis. Gain | I$_2$ | I$_1$ | D$_{51}$ W.Va. (sp) Hold |
| R$_{40}$ S.D. Re-elected | R$_{39}$ S.C. Re-elected | R$_{38}$ Okla. Re-elected | R$_{37}$ Ohio Hold | R$_{36}$ N.C. Re-elected | R$_{35}$ N.H. Hold | R$_{34}$ Mo. Hold | R$_{33}$ La. Re-elected | R$_{32}$ Ky. Hold | R$_{31}$ Kan. Hold |
| R$_{21}$ | R$_{22}$ | R$_{23}$ | R$_{24}$ Ala. Re-elected | R$_{25}$ Alaska Re-elected | R$_{26}$ Ariz. Re-elected | R$_{27}$ Fla. Hold | R$_{28}$ Ga. Re-elected | R$_{29}$ Idaho Re-elected | R$_{30}$ Iowa Re-elected |
| R$_{20}$ | R$_{19}$ | R$_{18}$ | R$_{17}$ | R$_{16}$ | R$_{15}$ | R$_{14}$ | R$_{13}$ | R$_{12}$ | R$_{11}$ |
| R$_1$ | R$_2$ | R$_3$ | R$_4$ | R$_5$ | R$_6$ | R$_7$ | R$_8$ | R$_9$ | R$_{10}$ |
| Key: | D$_#$ Democratic I$_#$ Independent R$_#$ Republican |

## Final pre-election predictions

Several sites and individuals publish predictions of competitive seats. These predictions look at factors such as the strength of the incumbent (if the incumbent is running for reelection) and the other candidates, and the state's partisan lean (reflected in part by the state's Cook Partisan Voting Index rating). The predictions assign ratings to each seat, indicating the predicted advantage that a party has in winning that seat.
Most election predictors used:
* "tossup": no advantage
* "tilt" (used by some predictors): advantage that is not quite as strong as "lean"
* "lean": slight advantage
* "likely" or "favored": significant, but surmountable, advantage
* "safe" or "solid": near-certain chance of victory
Where a site gives a percentage probability as its primary indicator of expected outcome, the chart below classifies a race as follows:
* Tossup: 50-55%
* Tilt: 56-60%
* Lean: 61-75%
* Likely: 76-93%
* Safe: 94-100%
| Constituency | Constituency | Incumbent | 2010 election ratings | 2010 election ratings | 2010 election ratings | 2010 election ratings | 2010 election ratings | 2010 election ratings |
| State | Senator | Last election | Cook | Rothenberg | RCP | Sabato | CQ Politics | Result |
| Alabama | Richard Shelby | 67.5% R | Safe R | Safe R | Safe R | Safe R | Safe R | Shelby 65.2% R |
| Alaska | Lisa Murkowski | 48.6% R | Likely R | Safe R | Likely R | Likely R | Likely R | Murkowski 39.5% R |
| Arizona | John McCain | 76.7% R | Safe R | Safe R | Safe R | Safe R | Safe R | McCain 59.2% R |
| Arkansas | Blanche Lincoln | 55.9% D | Lean R (flip) | Likely R (flip) | Safe R (flip) | Safe R (flip) | Lean R (flip) | Boozman 57.9% R (flip) |
| California | Barbara Boxer | 57.7% D | Tossup | Tilt D | Tossup | Lean D | Lean D | Boxer 52.2% D |
| Colorado | Michael Bennet | Appointed (2009) | Tossup | Tossup | Tossup | Lean R (flip) | Tossup | Bennet 48.1% D |
| Connecticut | Chris Dodd (retired) | 66.4% D | Lean D | Likely D | Lean D | Lean D | Lean D | Blumenthal 55.2% D |
| Delaware (special) | Ted Kaufman (retired) | Appointed (2009) | Likely D | Likely D | Likely D | Likely D | Likely D | Coons 56.6% D |
| Florida | George LeMieux (retired) | Appointed (2009) | Safe R | Safe R | Likely R | Safe R | Likely R | Rubio 48.9% R |
| Georgia | Johnny Isakson | 57.9% R | Safe R | Safe R | Safe R | Safe R | Safe R | Isakson 58.3% R |
| Hawaii | Daniel Inouye | 75.5% D | Safe D | Safe D | Safe D | Safe D | Safe D | Inouye 74.8% D |
| Idaho | Mike Crapo | 99.2% R | Safe R | Safe R | Safe R | Safe R | Safe R | Crapo 71.2% R |
| Illinois | Roland Burris (retired) | Appointed (2009) | Tossup | Tilt R (flip) | Tossup | Lean R (flip) | Tossup | Kirk 48.0% R (flip) |
| Indiana | Evan Bayh (retired) | 61.7% D | Safe R (flip) | Lean R (flip) | Likely R (flip) | Likely R (flip) | Safe R (flip) | Coats 54.6% R (flip) |
| Iowa | Chuck Grassley | 70.2% R | Safe R | Safe R | Safe R | Safe R | Safe R | Grassley 64.4% R |
| Kansas | Sam Brownback (retired) | 69.9% R | Safe R | Safe R | Safe R | Safe R | Safe R | Moran 70.1% R |
| Kentucky | Jim Bunning (retired) | 50.7% R | Lean R | Lean R | Lean R | Lean R | Lean R | Paul 55.7% R |
| Louisiana | David Vitter | 51.0% R | Lean R | Likely R | Likely R | Likely R | Likely R | Vitter 56.6% R |
| Massachusetts (special) | Paul G. Kirk (retired) | Appointed (2009) | Tossup | Lean R (flip) | Tossup | Tossup | Tossup | Brown 51.6% R (flip) |
| Maryland | Barbara Mikulski | 64.8% D | Safe D | Safe D | Safe D | Safe D | Safe D | Mikulski 62.2% D |
| Missouri | Kit Bond (retired) | 56.1% R | Lean R | Lean R | Likely R | Likely R | Lean R | Blunt 54.2% R |
| Nevada | Harry Reid | 61.0% D | Tossup | Tossup | Tossup | Lean R (flip) | Tossup | Reid 50.3% D |
| New Hampshire | Judd Gregg (retired) | 66.2% R | Lean R | Safe R | Lean R | Likely R | Lean R | Ayotte 60.1% R |
| New York (regular) | Chuck Schumer | 71.2% D | Safe D | Safe D | Safe D | Safe D | Safe D | Schumer 66.3% D |
| New York (special) | Kirsten Gillibrand | Appointed (2009) | Safe D | Safe D | Likely D | Safe D | Safe D | Gillibrand 63.0% D |
| North Carolina | Richard Burr | 51.6% R | Likely R | Likely R | Likely R | Likely R | Likely R | Burr 54.8% R |
| North Dakota | Byron Dorgan (retired) | 68.3% D | Safe R (flip) | Safe R (flip) | Safe R (flip) | Safe R (flip) | Safe R (flip) | Hoeven 76.1% R (flip) |
| Ohio | George Voinovich (retired) | 63.9% R | Safe R | Safe R | Safe R | Likely R | Safe R | Portman 56.8% R |
| Oklahoma | Tom Coburn | 52.8% R | Safe R | Safe R | Safe R | Safe R | Safe R | Coburn 70.6% R |
| Oregon | Ron Wyden | 63.4% D | Safe D | Safe D | Likely D | Safe D | Safe D | Wyden 57.2% D |
| Pennsylvania | Arlen Specter (lost renomination) | 52.6% R | Tossup | Tilt R (flip) | Tossup | Lean R (flip) | Tossup | Toomey 51.0% R (flip) |
| South Carolina | Jim DeMint | 53.7% R | Safe R | Safe R | Safe R | Safe R | Safe R | DeMint 61.5% R |
| South Dakota | John Thune | 60.6% R | Safe R | Safe R | Safe R | Safe R | Safe R | Thune 100.0% R |
| Utah | Bob Bennett (lost renomination) | 68.6% R | Safe R | Safe R | Safe R | Safe R | Safe R | Lee 61.6% R |
| Vermont | Patrick Leahy | 70.6% D | Safe D | Safe D | Safe D | Safe D | Safe D | Leahy 64.4% D |
| Washington | Patty Murray | 55.0% D | Tossup | Tossup | Tossup | Lean D | Tossup | Murray 52.4% |
| West Virginia (special) | Carte Goodwin (retired) | Appointed (2010) | Tossup | Tilt D | Tossup | Lean D | Tossup | Manchin 53.5% |
| Wisconsin | Russ Feingold | 55.3% D | Lean R (flip) | Lean R (flip) | Lean R (flip) | Lean R (flip) | Lean R (flip) | Johnson 51.6% R (flip) |

## Gains and losses
### Retirements

Three Democrats and six Republicans retired rather than seek re-election. Three Democrats retired rather than seek election to finish the unexpired term and one Democrat retired rather than seek election to finish the unexpired term and election to a full term.
| State | Senator | Replaced by |
| Connecticut | Chris Dodd | Richard Blumenthal |
| Delaware (special) | Ted Kaufman | Chris Coons |
| Florida | George LeMieux | Marco Rubio |
| Illinois | Roland Burris | Mark Kirk |
| Indiana | Evan Bayh | Dan Coats |
| Kansas | Sam Brownback | Jerry Moran |
| Kentucky | Jim Bunning | Rand Paul |
| Massachusetts (special) | Paul G. Kirk | Scott Brown |
| Missouri | Kit Bond | Roy Blunt |
| New Hampshire | Judd Gregg | Kelly Ayotte |
| North Dakota | Byron Dorgan | John Hoeven |
| Ohio | George Voinovich | Rob Portman |
| West Virginia (special) | Carte Goodwin | Joe Manchin |

### Defeats

Three Democrats and one Republican sought re-election but lost in either the primary or general election.
| State | Senator | Replaced by |
| Arkansas | Blanche Lincoln | John Boozman |
| Pennsylvania | Arlen Specter | Pat Toomey |
| Utah | Bob Bennett | Mike Lee |
| Wisconsin | Russ Feingold | Ron Johnson |

### Post-election changes

One Republican resigned on May 3, 2011, and was replaced by an appointee.
| State | Senator | Replaced by |
| Nevada (Class 1) | John Ensign | Dean Heller |

## Race summary
### Special elections during the 111th Congress

In these special elections, the winner was seated in the fall of 2010 (excluding Massachusetts), once they qualified and their elections were certified. Sorted by election date, then state, then class.
| State | Incumbent | Incumbent | Incumbent | Result | Candidates |
| State | Senator | Party | Electoral history | Result | Candidates |
| Massachusetts (Class 1) | Paul G. Kirk | Democratic | 2009 (appointed) | Interim appointee retired. New senator elected January 19, 2010 and seated February 4, 2010. Republican gain. | ▌Y Scott Brown (Republican) 51.9% ▌Martha Coakley (Democratic) 47.1% ▌Joseph L. Kennedy (Libertarian) 1.0% |
| Delaware (Class 2) | Ted Kaufman | Democratic | 2009 (appointed) | Interim appointee retired. New senator elected November 2, 2010 and seated November 15, 2010. Democratic hold. | ▌Y Chris Coons (Democratic) 56.6% ▌Christine O'Donnell (Republican) 40.0% ▌Glenn Miller (Independent) 2.7% ▌James Rash (Libertarian) 0.7% |
| Illinois (Class 3) | Roland Burris | Democratic | 2009 (appointed) | Interim appointee retired. New senator elected November 2, 2010 and seated November 29, 2010. Winner also elected to next term; see below. Republican gain. | ▌Y Mark Kirk (Republican) 48.2% ▌Alexi Giannoulias (Democratic) 46.3% ▌LeAlan Jones (Green) 3.2% ▌Mike Labino (Libertarian) 2.4% |
| New York (Class 1) | Kirsten Gillibrand | Democratic | 2009 (appointed) | Interim appointee elected November 2, 2010. | ▌Y Kirsten Gillibrand (Democratic) 59.6% ▌Joe DioGuardi (Republican) 33.3% Others ▌Cecile A. Lawrence (Green) 0.8% ▌John Clifton (Libertarian) 0.4% ▌Joseph Huff (Rent Is Too Damn High) 0.4% |
| West Virginia (Class 1) | Carte Goodwin | Democratic | 2010 (appointed) | Interim appointee retired. New senator elected November 2, 2010 and seated November 15, 2010. Democratic hold. | ▌Y Joe Manchin (Democratic) 53.5% ▌John Raese (Republican) 43.4% Others ▌Jesse Johnson (Mountain) 1.9% ▌Jeff Becker (Constitution) 1.2% |

### Elections leading to the next Congress

In these regular elections, the winners were elected for the term beginning January 3, 2011; ordered by state.
All of the elections involved the Class 3 seats.
| State | Incumbent | Incumbent | Incumbent | Result | Candidates |
| State | Senator | Party | Electoral history | Result | Candidates |
| Alabama | Richard Shelby | Republican | 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Richard Shelby (Republican) 65.3% ▌William G. Barnes (Democratic) 34.7% |
| Alaska | Lisa Murkowski | Republican | 2002 (appointed) 2004 | Incumbent lost renomination, but was re-elected as a write-in candidate. | ▌Y Lisa Murkowski (Republican write-in) 39.5% ▌Joe Miller (Republican) 35.5% ▌Scott McAdams (Democratic) 23.5% |
| Arizona | John McCain | Republican | 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y John McCain (Republican) 59.2% ▌Rodney Glassman (Democratic) 34.7% ▌David Nolan (Libertarian) 4.7% ▌Jerry Joslyn (Green) 1.4% |
| Arkansas | Blanche Lincoln | Democratic | 1998 2004 | Incumbent lost re-election. Republican gain. | ▌Y John Boozman (Republican) 58.0% ▌Blanche Lincoln (Democratic) 36.9% ▌Trevor Drown (Independent) 3.3% ▌John Gray (Green) 1.9% |
| California | Barbara Boxer | Democratic | 1992 1998 2004 | Incumbent re-elected. | ▌Y Barbara Boxer (Democratic) 52.1% ▌Carly Fiorina (Republican) 42.5% Others ▌Gail Lightfoot (Libertarian) 1.8% ▌Marsha Feinland (Peace and Freedom) 1.3% ▌Edward Noonan (American Independent) 1.3% ▌Duane Roberts (Green) 1.2% |
| Colorado | Michael Bennet | Democratic | 2009 (appointed) | Interim appointee elected. | ▌Y Michael Bennet (Democratic) 48.1% ▌Ken Buck (Republican) 46.3% Others ▌Bob Kinsey (Green) 2.2% ▌Maclyn Stringer (Libertarian) 1.3% |
| Connecticut | Chris Dodd | Democratic | 1980 1986 1992 1998 2004 | Incumbent retired. Democratic hold. | ▌Y Richard Blumenthal (Democratic) 55.1% ▌Linda McMahon (Republican) 43.3% Others ▌Warren Mosler (Independent) 1.0% ▌John Mertens (CfL) 0.6% |
| Florida | George LeMieux | Republican | 2009 (appointed) | Interim appointee retired. Republican hold. | ▌Y Marco Rubio (Republican) 48.9% ▌Charlie Crist (Independent) 29.7% ▌Kendrick Meek (Democratic) 20.1% ▌Alexander Snitker (Libertarian) 0.5% |
| Georgia | Johnny Isakson | Republican | 2004 | Incumbent re-elected. | ▌Y Johnny Isakson (Republican) 58.1% ▌Mike Thurmond (Democratic) 39.2% ▌Chuck Donovan (Libertarian) 2.7% |
| Hawaii | Daniel Inouye | Democratic | 1962 1968 1974 1980 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Daniel Inouye (Democratic) 74.8% ▌Campbell Cavasso (Republican) 21.6% Others ▌James Brewer (Green) 2.1% ▌Jeff Mallan (Libertarian) 0.8% |
| Idaho | Mike Crapo | Republican | 1998 2004 | Incumbent re-elected. | ▌Y Mike Crapo (Republican) 71.1% ▌Tom Sullivan (Democratic) 25.0% ▌Randy Bergquist (Constitution) 3.9% |
| Illinois | Roland Burris | Democratic | 2009 (appointed) | Interim appointee retired. Kirk was also elected to finish the previous term; see above. Republican gain. | ▌Y Mark Kirk (Republican) 48.2% ▌Alexi Giannoulias (Democratic) 46.3% ▌LeAlan Jones (Green) 3.2% ▌Mike Labino (Libertarian) 2.4% |
| Indiana | Evan Bayh | Democratic | 1998 2004 | Incumbent retired. Republican gain. | ▌Y Dan Coats (Republican) 54.6% ▌Brad Ellsworth (Democratic) 40.0% ▌Rebecca Sink-Burris (Libertarian) 5.4% |
| Iowa | Chuck Grassley | Republican | 1980 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Chuck Grassley (Republican) 64.5% ▌Roxanne Conlin (Democratic) 33.2% ▌John Heiderscheit (Libertarian) 2.3% |
| Kansas | Sam Brownback | Republican | 1996 (special) 1998 2004 | Incumbent retired to run for Governor of Kansas. Republican hold. | ▌Y Jerry Moran (Republican) 70.3% ▌Lisa Johnston (Democratic) 26.2% Others ▌Michael Dann (Libertarian) 2.1% ▌Joe Bellis (Reform) 1.4% |
| Kentucky | Jim Bunning | Republican | 1998 2004 | Incumbent retired. Republican hold. | ▌Y Rand Paul (Republican) 55.8% ▌Jack Conway (Democratic) 44.2% |
| Louisiana | David Vitter | Republican | 2004 | Incumbent re-elected. | ▌Y David Vitter (Republican) 56.6% ▌Charlie Melançon (Democratic) 37.7% Others ▌Randall Hayes (Libertarian) 1.1% ▌Michael Brown (Independent) 0.8% |
| Maryland | Barbara Mikulski | Democratic | 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Barbara Mikulski (Democratic) 61.8% ▌Eric Wargotz (Republican) 36.3% Others ▌Kenniss Henry (Green) 1.1% ▌Richard Shawver (Constitution) 0.8% |
| Missouri | Kit Bond | Republican | 1986 1992 1998 2004 | Incumbent retired. Republican hold. | ▌Y Roy Blunt (Republican) 54.3% ▌Robin Carnahan (Democratic) 40.6% ▌Jonathan Dine (Libertarian) 3.0% ▌Jerry Beck (Constitution) 2.1% |
| Nevada | Harry Reid | Democratic | 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Harry Reid (Democratic) 50.2% ▌Sharron Angle (Republican) 44.6% Others None of These Candidates 2.2% ▌Scott Ashjian (Tea) 0.8% |
| New Hampshire | Judd Gregg | Republican | 1992 1998 2004 | Incumbent retired. Republican hold. | ▌Y Kelly Ayotte (Republican) 60.2% ▌Paul Hodes (Democratic) 36.7% Others ▌Chris Booth (Independent) 2.0% ▌Ken Blevens (Libertarian) 1.0% |
| New York | Chuck Schumer | Democratic | 1998 2004 | Incumbent re-elected. | ▌Y Chuck Schumer (Democratic) 66.3% ▌Jay Townsend (Republican) 32.2% Others ▌Colia Clark (Green) 1.0% ▌Randy Credico (Libertarian) 0.6% |
| North Carolina | Richard Burr | Republican | 2004 | Incumbent re-elected. | ▌Y Richard Burr (Republican) 55.0% ▌Elaine Marshall (Democratic) 42.9% ▌Mike Beitler (Libertarian) 2.1% |
| North Dakota | Byron Dorgan | Democratic-NPL | 1992 1998 2004 | Incumbent retired. Republican gain. | ▌Y John Hoeven (Republican) 76.2% ▌Tracy Potter (Democratic–NPL) 22.2% ▌Keith Hanson (Libertarian) 1.6% |
| Ohio | George Voinovich | Republican | 1998 2004 | Incumbent retired. Republican hold. | ▌Y Rob Portman (Republican) 57.3% ▌Lee Fisher (Democratic) 39.0% Others ▌Eric Deaton (Constitution) 1.7% ▌Michael Pryce (Independent) 1.3% |
| Oklahoma | Tom Coburn | Republican | 2004 | Incumbent re-elected. | ▌Y Tom Coburn (Republican) 70.5% ▌Jim Rogers (Democratic) 26.1% Others ▌Stephen Wallace (Independent) 2.5% ▌Ronald Dwyer (Independent) 0.9% |
| Oregon | Ron Wyden | Democratic | 1996 (special) 1998 2004 | Incumbent re-elected. | ▌Y Ron Wyden (Democratic) 57.2% ▌Jim Huffman (Republican) 39.4% Others ▌Bruce Cronk (Working Families) 1.3% ▌Marc Delphine (Libertarian) 1.1% ▌Rick Staggenborg (Progressive) 1.0% |
| Pennsylvania | Arlen Specter | Democratic | 1980 1986 1992 1998 2004 | Incumbent lost renomination. Republican gain. | ▌Y Pat Toomey (Republican) 51.01% ▌Joe Sestak (Democratic) 48.99% |
| South Carolina | Jim DeMint | Republican | 2004 | Incumbent re-elected. | ▌Y Jim DeMint (Republican) 62.4% ▌Alvin Greene (Democratic) 28.2% ▌Tom Clements (Green) 9.4% |
| South Dakota | John Thune | Republican | 2004 | Incumbent re-elected. | ▌Y John Thune (Republican) Unopposed |
| Utah | Bob Bennett | Republican | 1992 1998 2004 | Incumbent lost renomination. Republican hold. | ▌Y Mike Lee (Republican) 61.6% ▌Sam Granato (Democratic) 32.8% ▌Scott Bradley (Constitution) 5.7% |
| Vermont | Patrick Leahy | Democratic | 1974 1980 1986 1992 1998 2004 | Incumbent re-elected. | ▌Y Patrick Leahy (Democratic) 64.4% ▌Len Britton (Republican) 30.9% Others ▌Daniel Freilich (Independent) 1.5% ▌Cris Ericson (Independent) 1.1% ▌Stephen Cain (Independent) 1.0% |
| Washington | Patty Murray | Democratic | 1992 1998 2004 | Incumbent re-elected. | ▌Y Patty Murray (Democratic) 52.4% ▌Dino Rossi (Republican) 47.6% |
| Wisconsin | Russ Feingold | Democratic | 1992 1998 2004 | Incumbent lost re-election. Republican gain. | ▌Y Ron Johnson (Republican) 51.9% ▌Russ Feingold (Democratic) 47.0% ▌Rob Taylor (Constitution) 1.1% |

## Closest races

Seven November races, as well as the Massachusetts special election in January, had margins less than 10%:
| District | Winner | Margin |
| Illinois | Republican (flip) | 1.6% |
| Colorado | Democratic | 1.7% |
| Pennsylvania | Republican (flip) | 2.0% |
| Alaska | Republican | 4.0% |
| Washington | Democratic | 4.7% |
| Massachusetts | Republican (flip) | 4.8% |
| Wisconsin | Republican (flip) | 4.8% |
| Nevada | Democratic | 5.7% |
California was the tipping point state, where Barbara Boxer (D) defeated Carly Fiorina (R) by a margin of 10.0%.

## Alabama

Incumbent Republican Richard Shelby won re-election to a fifth term. On November 9, 1994, Shelby switched his party affiliation from Democratic to Republican, one day after the Republicans won control of both houses in the midterm elections, giving the Republicans a 53–47 majority in the Senate. He won his first full term as a Republican in 1998 by a large margin, and faced no significant opposition in 2004 and 2010.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Richard Shelby (Incumbent) | 405,042 | 84.4% |
| | Republican | Clint Moser | 75,190 | 15.6% |
| Total votes | Total votes | Total votes | 479,189 | 100.0% |
Shelby had over $17 million in the bank, one of the highest of any candidate in the country. He had become even more popular in his opposition to the Troubled Asset Relief Program (TARP) and the Emergency Economic Stabilization Act of 2008, as the ranking member of the Senate Banking Committee.
In May, Shelby told reporters "I don't even know who my opponent is."
2010 United States Senate election in Alabama :
| Party | Party | Candidate | Votes | % |
| | Republican | Richard Shelby (Incumbent) | 968,181 | 65.3% |
| | Democratic | William G. Barnes | 515,619 | 34.7% |
| Total votes | Total votes | Total votes | 1,482,910 | 100.0% |
| Turnout | Turnout | Turnout | | N/A |
| | Republican hold | Republican hold | Republican hold | Republican hold |

## Alaska

The November general election in Alaska was preceded by primary elections which were held August 24, 2010. Scott McAdams, the Mayor of Sitka, became the Democratic nominee and Joe Miller, an attorney and former federal magistrate, became the Republican nominee after defeating incumbent Senator Lisa Murkowski in the Republican primary.
Murkowski garnered more than 100,000 write-in votes in the general election, many of which were challenged by Miller for various errors including minor misspellings. The appeal was denied Even if all the challenged votes were thrown out, Murkowski would have still had a lead of over 2,100 votes.
Alaska Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Scott McAdams | 18,035 | 49.99% |
| | Democratic | Jacob Seth Kern | 6,913 | 19.16% |
| | Libertarian | David Haase | 5,793 | 16.06% |
| | Democratic | Frank Vondersaar | 5,339 | 14.80% |
| Total votes | Total votes | Total votes | 36,080 | 100.00% |
| Turnout | Turnout | Turnout | | 32% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Joe Miller | 55,878 | 50.91% |
| | Republican | Lisa Murkowski (Incumbent) | 53,872 | 49.09% |
| Total votes | Total votes | Total votes | 109,750 | 100.00% |
| Turnout | Turnout | Turnout | | 32% |
Alaska general election :
| Party | Party | Candidate | Votes | % |
| | Write-In | Lisa Murkowski (Incumbent) | 101,091 | 39.49% |
| | Republican | Joe Miller | 90,839 | 35.49% |
| | Democratic | Scott McAdams | 60,045 | 23.46% |
| | Libertarian | David Haase | 1,459 | 0.57% |
| | Independent | Timothy Carter | 927 | 0.36% |
| | Independent | Ted Gianoutsos | 458 | 0.18% |
| | Write-In | Other write-in votes | 1,143 | 0.44% |
| Invalid or blank votes | Invalid or blank votes | Invalid or blank votes | 2,784 | 1.08% |
| Total votes | Total votes | Total votes | 258,746 | 100.00% |
| Turnout | Turnout | Turnout | | 52.3% |

## Arizona

Incumbent Republican John McCain, who returned to the Senate after losing the presidency to Barack Obama in the 2008 presidential election, ran for re-election to a fifth term and won.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Rodney Glassman | 86,881 | 34.7% |
| | Democratic | Cathy Eden | 66,421 | 26.5% |
| | Democratic | John Dougherty | 60,262 | 24.1% |
| | Democratic | Randy Parraz | 36,637 | 14.6% |
| Total votes | Total votes | Total votes | 250,201 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | John McCain (Incumbent) | 284,374 | 56.2% |
| | Republican | J.D. Hayworth | 162,502 | 32.1% |
| | Republican | Jim Deakin | 59,447 | 11.7% |
| Total votes | Total votes | Total votes | 506,323 | 100.0% |
After spending over $20 million during the primaries, McCain still had more than $1million cash on hand after the primary election. Glassman criticized McCain on women's issues. In August 2010, Glassman released a TV advertisement called "Arizona First."
2010 United States Senate election in Arizona :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | John McCain (Incumbent) | 1,005,615 | 59.07% | −17.67% |
| | Democratic | Rodney Glassman | 592,011 | 34.78% | +14.16% |
| | Libertarian | David Nolan | 80,097 | 4.71% | +2.06% |
| | Green | Jerry Joslyn | 24,603 | 1.45% | N/A |
| Majority | Majority | Majority | 413,604 | 24.30% | |
| Total votes | Total votes | Total votes | 1,702,326 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Arkansas

Incumbent Democrat Blanche Lincoln ran for re-election to a third term, but lost to Republican nominee John Boozman. Boozman became the first Republican in 138 years to win the seat. Arkansas had previously only elected one Republican senator since the Reconstruction, who was defeated after his first term in 2002 by Mark Pryor.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Blanche Lincoln (Incumbent) | 146,579 | 44.5% |
| | Democratic | Bill Halter | 140,081 | 42.5% |
| | Democratic | D.C. Morrison | 42,695 | 13.0% |
| Total votes | Total votes | Total votes | 329,355 | 100.0% |
Democratic primary election runoff :
| Party | Party | Candidate | Votes | % |
| | Democratic | Blanche Lincoln (Incumbent) | 134,758 | 52.0% |
| | Democratic | Bill Halter | 124,405 | 48.0% |
| Total votes | Total votes | Total votes | 259,163 | 100.0% |
The Republican primary was held May 18, 2010, with early voting from May 3–17.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | John Boozman | 75,010 | 52.7% |
| | Republican | Jim Holt | 24,826 | 17.5% |
| | Republican | Gilbert Baker | 16,540 | 11.6% |
| | Republican | Conrad Reynolds | 7,128 | 5.0% |
| | Republican | Curtis Coleman | 6,928 | 4.9% |
| | Republican | Kim Hendren | 5,551 | 3.9% |
| | Republican | Randy Alexander | 4,389 | 3.1% |
| | Republican | Fred Ramey | 1,888 | 1.3% |
| Total votes | Total votes | Total votes | 142,260 | 100.0% |
2010 United States Senate election in Arkansas :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | John Boozman | 451,617 | 57.90% | +13.83% |
| | Democratic | Blanche Lincoln (Incumbent) | 288,156 | 36.95% | −18.95% |
| | Libertarian | Trevor Drown | 25,234 | 3.24% | +3.24% |
| | Green | John Gray | 14,430 | 1.85% | +1.85% |
| Majority | Majority | Majority | 163,461 | 20.95% | |
| Total votes | Total votes | Total votes | 779,437 | 100.00% | |
| Turnout | Turnout | Turnout | | | |
| | Republican gain from Democratic | Republican gain from Democratic | Swing | | |

## California

Incumbent Democrat Barbara Boxer won re-election to a fourth term.
In 2009, Boxer was criticized for correcting a general who called her "ma'am". Brigadier General Michael Walsh was testifying on the Louisiana coastal restoration process in the wake of Hurricane Katrina and answered Boxer's query with "ma'am" when Boxer interrupted him. "Do me a favor," Boxer said. "can you say 'senator' instead of 'ma'am?'" "Yes, ma'am," Walsh interjected. "It's just a thing, I worked so hard to get that title, so I'd appreciate it. Thank you," she said. The Army's guide to protocol instructs service members to call members of the U.S. Senate "sir", "ma'am" or "senator". Fiorina used this incident prominently in campaign ads, as did David Zucker, who directed a humorous commercial for RightChange.com titled 'Call Me Senator.' In February 2010, Carly Fiorina put out a campaign ad attacking Republican rival Tom Campbell featuring a "demon sheep", creating international, mostly negative, publicity.
California Democratic Senate primary, 2010 :
| Candidate | Candidate | Votes | % |
| Barbara Boxer (Incumbent) | Barbara Boxer (Incumbent) | 1,957,920 | 81.0% |
| Brian Quintana | Brian Quintana | 338,442 | 13.9% |
| Mickey Kaus | Mickey Kaus | 123,573 | 5.1% |
| Total votes | Total votes | 2,419,935 | 100.0% |
California Republican Senate primary, 2010 :
| Candidate | Candidate | Votes | % |
| Carly Fiorina | Carly Fiorina | 1,315,429 | 56.4% |
| Tom Campbell | Tom Campbell | 504,289 | 21.7% |
| Chuck DeVore | Chuck DeVore | 452,577 | 19.3% |
| Al Ramirez | Al Ramirez | 42,149 | 1.8% |
| Tim Kalemkarian | Tim Kalemkarian | 19,598 | 0.8% |
| Total votes | Total votes | 2,334,042 | 100.0% |
California general election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Barbara Boxer (Incumbent) | 5,218,441 | 52.2% |
| | Republican | Carly Fiorina | 4,217,366 | 42.2% |
| | Libertarian | Gail Lightfoot | 175,242 | 1.8% |
| | Peace and Freedom | Marsha Feinland | 135,093 | 1.4% |
| | Green | Duane Roberts | 128,510 | 1.2% |
| | American Independent | Edward Noonan | 125,441 | 1.2% |
| | Write-ins | | 67 | <0.1% |
| Total votes | Total votes | Total votes | 10,000,160 | 100.0% |

## Colorado

In December 2008, President-elect Barack Obama selected incumbent U.S. Senator Ken Salazar to become U.S. Secretary of the Interior. After Salazar resigned from his seat, Democratic Governor Bill Ritter appointed Denver Public Schools Superintendent Michael Bennet to fill the seat, who won re-election to his first full term.
Colorado Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Michael Bennet (Incumbent) | 183,225 | 54.2% |
| | Democratic | Andrew Romanoff | 154,961 | 45.8% |
| Total votes | Total votes | Total votes | 338,186 | 100.00% |
Colorado Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Ken Buck | 209,638 | 51.6% |
| | Republican | Jane Norton | 196,954 | 48.4% |
| Total votes | Total votes | Total votes | 406,592 | 100.0% |
This was one of the most expensive elections in the 2010 cycle, with more than $50 million spent total, including over $35 million in outside spending. Conservative third party groups hammered Bennet for voting 92% of the time with the Democratic leadership, including voting for healthcare reform and the stimulus package. Liberal third party groups called Buck extremist. Bennet focused on attacking Buck's views on abortion, which he believed should be banned including those of cases of rape and incest. He was also attacked for wanting to eliminate the Seventeenth Amendment and refusing to prosecute an alleged rapist as Weld County district attorney. Planned Parenthood mounted a mail campaign, targeting women voters with the warning that "Colorado women can't trust Ken Buck." Bennet won the women vote by 17 points according to exit polls. After the election, Buck conceded to the Denver Post that the main reason why he lost is because of social issues.
2010 United States Senate election in Colorado :
| Party | Party | Candidate | Votes | % |
| | Democratic | Michael Bennet (Incumbent) | 851,590 | 48.1% |
| | Republican | Ken Buck | 822,731 | 46.4% |
| | Green | Bob Kinsey | 38,768 | 2.2% |
| | Libertarian | Maclyn Stringer | 22,589 | 1.3% |
| | Independent | Jason Napolitano | 19,415 | 1.1% |
| | Independent | Charley Miller | 11,330 | 0.6% |
| | Independent | J. Moromisato | 5,767 | 0.3% |
| Total votes | Total votes | Total votes | 1,772,190 | 100.0% |
| Turnout | Turnout | Turnout | | N/A |

## Connecticut

Incumbent Democrat Christopher Dodd suffered from dropping approval ratings in the past few years due to major controversies, leading him to announce in January 2010 that he would retire, instead of seeking a sixth term. As Dodd was a Democrat, Richard Blumenthal, incumbent State Attorney General, announced on the same day that he would run for Dodd's seat. The Connecticut Democratic Party nominated Blumenthal on May 21. Businesswoman Linda McMahon won the state party's nominating convention and the August 10 Republican primary to become the Republican candidate.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Linda McMahon | 60,479 | 49.44% |
| | Republican | Rob Simmons | 34,011 | 27.80% |
| | Republican | Peter Schiff | 27,831 | 22.75% |
| Total votes | Total votes | Total votes | 122,321 | 100.00% |
2010 United States Senate election in Connecticut :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Richard Blumenthal | 636,040 | 55.16% | −11.20% |
| | Republican | Linda E. McMahon | 498,341 | 43.22% | +11.08% |
| | Independent | Warren B. Mosler | 11,275 | 0.98% | N/A |
| | Independent | Dr. John Mertens | 6,735 | 0.58% | N/A |
| | Write-In | Write-in candidates (8) | 724 | 0.06% | N/A |
| Majority | Majority | Majority | 137,755 | 11.95% | |
| Total votes | Total votes | Total votes | 1,153,115 | 100.00% | |
| | Democratic hold | Democratic hold | Democratic hold | Democratic hold | Democratic hold |
Note: Blumenthal also appeared on the line of the Connecticut Working Families Party and received 30,836 votes on it. His Working Families and Democratic votes have been aggregated together on this table.

## Delaware (special)

This was a special election to fill Delaware's Class 2 Senate seat, then held by Ted Kaufman, an appointee. The seat had been previously held by long-time Senator Joe Biden, who vacated it when he became Vice President of the United States in 2009.
Delaware Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Christine O'Donnell | 30,561 | 53.1% |
| | Republican | Michael N. Castle | 27,021 | 46.9% |
| Total votes | Total votes | Total votes | 57,582 | 100.0% |
2010 United States Senate special election in Delaware :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Chris Coons | 174,012 | 56.61% | −8.07% |
| | Republican | Christine O'Donnell | 123,053 | 40.03% | +4.72% |
| | Independent Party | Glenn Miller | 8,201 | 2.67% | |
| | Libertarian | James Rash | 2,101 | 0.69% | |
| Majority | Majority | Majority | 50,959 | 16.58% | −12.79% |
| Total votes | Total votes | Total votes | 307,367 | 100.00% | |
| | Democratic hold | Democratic hold | Swing | | |

## Florida

Incumbent Republican Senator Mel Martínez, who was elected in a very close race against Democrat Betty Castor with 49% of the vote in 2004, announced on December 2, 2008, that he would not run for re-election to a second term, then announcing on August 7, 2009, that he would resign prior to the end of his term. The Governor of Florida, Republican Charlie Crist, was required to appoint a successor and he chose his former Chief of Staff, George LeMieux. LeMieux, a placeholder who did not run in the election, replaced Martínez in the Senate on September 10, 2009.
Crist publicly announced he was running for the seat in mid-2009. When he declared his candidacy, he received many Republican endorsements, including the National Republican Senatorial Committee, Martínez, and 2008 Republican presidential nominee John McCain. However, his support of the American Recovery and Reinvestment Act of 2009 hurt his popularity among conservatives, and Tea Party candidate Marco Rubio, the former Speaker of the Florida House of Representatives, surged in the polls. In April 2010, Crist announced he would drop out of the Republican primary and run as an Independent. The National Republican Senatorial Committee withdrew its endorsement of Crist and demanded a refund of its campaign funds that it provided for the Crist campaign. Rubio went on to win the Republican primary against only token opposition.
Polling initially showed Crist neck and neck with Rubio, but by the end of August Rubio opened up a solid and consistent lead. He was supported by Republican and some Independent voters whereas Democratic and other Independents were split between Crist and Meek. Rubio went on to win the election with 49% of the vote to Crist's 30% and Meek's 20%.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Marco Rubio | 1,059,513 | 84.6% |
| | Republican | William Kogut | 111,584 | 8.9% |
| | Republican | William Escoffery | 81,873 | 6.5% |
| Total votes | Total votes | Total votes | 1,252,970 | 100.0% |
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Kendrick Meek | 522,942 | 57.4% |
| | Democratic | Jeff Greene | 283,370 | 31.1% |
| | Democratic | Glenn Burkett | 59,575 | 6.5% |
| | Democratic | Maurice Ferré | 44,506 | 4.9% |
| Total votes | Total votes | Total votes | 910,393 | 100.0% |
2010 United States Senate election in Florida :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Marco Antonio Rubio | 2,645,743 | 48.89% | −0.54% |
| | Independent | Charles Joseph Crist Jr. | 1,607,549 | 29.71% | +29.71% |
| | Democratic | Kendrick Brett Meek | 1,092,936 | 20.20% | −28.12% |
| | Libertarian | Alexander Snitker | 24,850 | 0.46% | N/A |
| | Independent | Sue Askeland | 15,340 | 0.28% | N/A |
| | Independent | Rick Tyler | 7,394 | 0.14% | N/A |
| | Constitution | Bernie DeCastro | 4,792 | 0.09% | N/A |
| | Independent | Lewis Jerome Armstrong | 4,443 | 0.08% | N/A |
| | Independent | Bobbie Bean | 4,301 | 0.08% | N/A |
| | Independent | Bruce Riggs | 3,647 | 0.07% | N/A |
| | Write-ins | | 108 | 0.00% |
| Majority | Majority | Majority | 1,038,194 | 19.19% | +18.08% |
| Turnout | Turnout | Turnout | 5,411,106 | 48.25% | −22.67% |
| Total votes | Total votes | Total votes | 5,411,106 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Georgia

Incumbent Republican Johnny Isakson won re-election to a second term.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Michael Thurmond | 297,226 | 84.3% |
| | Democratic | RJ Hadley | 55,159 | 15.7% |
| Total votes | Total votes | Total votes | 352,385 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Johnny Isakson | 558,298 | 100.00% |
| Total votes | Total votes | Total votes | 558,298 | 100.00% |
2010 United States Senate election in Georgia :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Johnny Isakson (Incumbent) | 1,489,904 | 58.31% | +0.43% |
| | Democratic | Michael Thurmond | 996,516 | 39.00% | −0.98% |
| | Libertarian | Chuck Donovan | 68,750 | 2.69% | +0.55% |
| | Independent | Steve Davis (write-in) | 52 | 0.00% | N/A |
| | Independent | Raymond Beckworth (write-in) | 24 | 0.00% | N/A |
| | Independent | Brian Russell Brown (write-in) | 12 | 0.00% | N/A |
| Majority | Majority | Majority | 493,388 | 19.31% | |
| Total votes | Total votes | Total votes | 2,555,258 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Hawaii

Incumbent Democrat and President pro tempore Daniel Inouye won re-election to his ninth term.
Hawaii last elected a Republican Senator in 1970, and its current delegation to the United States Congress currently consists entirely of Democrats. Democrats have also won Hawaii's electoral votes in every presidential election since Ronald Reagan's landslide election in 1984. The exceptions at the time were then-Governor Linda Lingle (who was serving her second and final term) and then-U.S. Representative Charles Djou, both of whom were Republicans.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Daniel Inouye (Incumbent) | 188,400 | 88.3% |
| | Democratic | Andy Woerner | 25,016 | 11.7% |
| Total votes | Total votes | Total votes | 213,416 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Campbell Cavasso | 21,865 | 66.7% |
| | Republican | John Roco | 7,190 | 21.9% |
| | Republican | Eddie Pirkowski | 3,744 | 11.4% |
| Total votes | Total votes | Total votes | 32,790 | 100.0% |
2010 United States Senate election in Hawaii :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Daniel Inouye (Incumbent) | 277,228 | 74.81% | −0.70% |
| | Republican | Cam Cavasso | 79,939 | 21.57% | +0.58% |
| | Green | Jim Brewer | 7,762 | 2.09% | N/A |
| | Libertarian | Lloyd Jeffrey Mallen | 2,957 | 0.80% | −0.47% |
| | Independent | Jeff Jarrett | 2,697 | 0.73% | N/A |
| Majority | Majority | Majority | 197,289 | 53.24% | |
| Total votes | Total votes | Total votes | 370,583 | 100.00% | |
| | Democratic hold | Democratic hold | Swing | | |

## Idaho

Incumbent Republican Mike Crapo won re-election to a third term.
Idaho Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Mike Crapo (Incumbent) | 127,332 | 79.3% |
| | Republican | Claude "Skip" Davis | 33,150 | 20.7% |
| Total votes | Total votes | Total votes | 160,482 | 100.0% |
Idaho Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Tom Sullivan | 18,340 | 74.7% |
| | Democratic | William Bryk | 6,227 | 25.3% |
| Total votes | Total votes | Total votes | 24,567 | 100.0% |
Sullivan, a heavy underdog, criticized Crapo for being in Washington for too long saying "Senator Crapo has been in Congress for 18 years. The country is struggling, and I think it's time to make a change." Crapo emphasized his conservative record in Washington.
2010 United States Senate election in Idaho :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Michael Crapo (Incumbent) | 319,953 | 71.19% | −27.99% |
| | Democratic | Tom Sullivan | 112,057 | 24.93% | N/A |
| | Constitution | Randy Bergquist | 17,429 | 3.88% | N/A |
| Majority | Majority | Majority | 207,896 | 46.26% | |
| Total votes | Total votes | Total votes | 449,439 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Illinois

Incumbent Democrat Roland Burris did not run in 2010. He suffered from poor approval ratings and was investigated by the Sangamon County, Illinois State's Attorney for perjury. Although no criminal charges were filed against him, he faced an investigation by the Senate Ethics Committee.
There were two ballot items for the same seat: a regular election, to fill the Class 3 seat beginning with the 112th United States Congress beginning on January 3, 2011, and a special election, to fill that seat for the final weeks of the 111th Congress, replacing the temporary appointment of Roland Burris to the vacancy created by Barack Obama's election to the presidency.
A federal court ruled that the candidates appearing on the ballot for the replacement election would be the ones of the regular election, and that the special election would appear after the regular election on the ballot.
As of 2023, this was the last Senate election in Illinois won by a Republican.
Democratic primary election (February 2, 2010) :
| Party | Party | Candidate | Votes | % |
| | Democratic | Alexi Giannoulias | 351,120 | 38.9% |
| | Democratic | David Hoffman | 303,719 | 33.7% |
| | Democratic | Cheryle Jackson | 178,941 | 19.8% |
| | Democratic | Robert Marshall | 51,606 | 5.7% |
| | Democratic | Jacob Meister | 16,232 | 1.8% |
| Total votes | Total votes | Total votes | 901,618 | 100.0% |
Illinois Republican primary election (February 2, 2010) :
| Party | Party | Candidate | Votes | % |
| | Republican | Mark Kirk | 420,373 | 56.6% |
| | Republican | Patrick Hughes | 142,928 | 19.3% |
| | Republican | Donald Lowery | 66,357 | 8.9% |
| | Republican | Kathleen Thomas | 54,038 | 7.3% |
| | Republican | Andy Martin | 37,480 | 5.0% |
| | Republican | John Arrington | 21,090 | 2.8% |
| | Republican | Patricia Beard | 2 | .0003% |
| Total votes | Total votes | Total votes | 742,268 | 100.0% |
Illinois special election :
| Party | Party | Candidate | Votes | % |
| | Republican | Mark Kirk | 1,677,729 | 47.3% |
| | Democratic | Alexi Giannoulias | 1,641,486 | 46.3% |
| | Green | LeAlan Jones | 129,571 | 3.7% |
| | Libertarian | Michael Labno | 95,762 | 2.7% |
| | Write-in | Lowell Martin Seida | 4 | 0.0001% |
| Total votes | Total votes | Total votes | 3,545,984 | 100.00% |
Illinois regular election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Mark Kirk | 1,778,698 | 48.0% | +21.0% |
| | Democratic | Alexi Giannoulias | 1,719,478 | 46.4% | −25.6% |
| | Green | LeAlan Jones | 117,914 | 3.2% | N/A |
| | Libertarian | Michael Labno | 87,247 | 2.4% | +1.1% |
| | Write-in | Lowell Martin Seida | 4 | 0.0001% | N/A |
| | Write-ins | | 1,136 | <0.1% | N/A |
| Majority | Majority | Majority | 59,220 | 1.6% | −51.4% |
| Turnout | Turnout | Turnout | 3,704,473 | | −27.9% |
| | Republican gain from Democratic | Republican gain from Democratic | Swing | | |

## Indiana

Incumbent Democrat Evan Bayh decided in February 2010 to retire instead of seeking a third term shortly after former U.S. Senator Dan Coats announced his candidacy for Bayh's contested seat. No Democratic candidate submitted enough signatures by the deadline to run, leading Democratic officials to choose U.S. Congressman Brad Ellsworth to be the nominee. Coats won the election.
Indiana Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Dan Coats | 217,225 | 39.5% |
| | Republican | Marlin Stutzman | 160,981 | 29.2% |
| | Republican | John Hostettler | 124,494 | 22.6% |
| | Republican | Don Bates, Jr. | 24,664 | 4.5% |
| | Republican | Richard Behney | 23,005 | 4.2% |
| Total votes | Total votes | Total votes | 550,369 | 100.0% |
After Coats's win in the Republican primary, Ellsworth began to heavily criticize Coats for his ties to lobbyists. He called for more disclosure of the meetings lawmakers have with lobbyists, banning congressional staff from lobbying for six years after their congressional jobs, requiring Congress members to put all their investments in blind trusts, more disclosure of Senate candidates' personal financial information, and changes to the U.S. Senate filibuster rules. He proposed lowering number of votes required to break a filibuster to 55 from the current 60. In response to Ellsworth's charges, Coats published his lobbying record in an 815-page document.
Coats emphasized the individual issues rather than ethics reforms advocated by his opponent. He focused on Ellsworth's record of voting in support of the Economic Stimulus Act of 2008, cap-and-trade legislation, and health care bill. Coats opinion of the healthcare law was that "the only responsible solution ... is to repeal the Obama-Pelosi-Ellsworth health spending bill and quickly replace it with cost-effective, incremental pieces that will decrease costs, increase coverage and not break the bank."
Indiana election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Dan Coats | 952,116 | 54.60% | +17.37% |
| | Democratic | Brad Ellsworth | 697,775 | 40.01% | −21.64% |
| | Libertarian | Rebecca Sink-Burris | 94,330 | 5.39% | +4.27% |
| Majority | Majority | Majority | 254,341 | 14.58% | |
| Total votes | Total votes | Total votes | 1,743,921 | 100.00% | |
| | Republican gain from Democratic | Republican gain from Democratic | Swing | | |

## Iowa

Incumbent Republican Chuck Grassley won re-election to a sixth term.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Chuck Grassley (inc.) | 197,194 | 98.0% |
| | Republican | Write-ins | 3,926 | 2.0% |
| Total votes | Total votes | Total votes | 201,120 | 100.0% |
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Roxanne Conlin | 52,715 | 77.5% |
| | Democratic | Bob Krause | 8,728 | 12.9% |
| | Democratic | Tom Fiegen | 6,357 | 9.4% |
| | Democratic | Write-ins | 177 | 0.2% |
| Total votes | Total votes | Total votes | 67,977 | 100.0% |
Incumbent Chuck Grassley started the campaign moderately popular, but his approval ratings dropped somewhat during the campaign. However, the seat continued to be considered to be "Safe Republican" by many sources, with CQ Politics noting that Grassley is "one of Iowa's most durable politicians."
Conlin described herself as a "prairie progressive." She supported the recent landmark case of Varnum v. Brien, which legalized gay marriage in the state. She also supported repeal of "don't ask, don't tell."
Before the election, former political advisor John Maxwell claimed that Grassley would have his toughest race since his first U.S. Senate election in 1980, where he defeated incumbent John Culver with 53% of the vote. Grassley won all of his four re-election bids with nearly 70% of the vote against unknown opponents. Grassley won the election with 64.51% of the vote.
2010 United States Senate election in Iowa :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Chuck Grassley (Incumbent) | 718,215 | 64.35% | −5.83% |
| | Democratic | Roxanne Conlin | 371,686 | 33.30% | +5.43% |
| | Libertarian | John Heiderscheit | 25,290 | 2.27% | |
| | Write-ins | | 872 | 0.08% | |
| Majority | Majority | Majority | 346,529 | 31.05% | −11.26% |
| Turnout | Turnout | Turnout | 1,116,063 | | |
| | Republican hold | Republican hold | Swing | | |

## Kansas

Incumbent Republican Sam Brownback retired to run for Governor of Kansas, instead of seeking a third term. Republican nominee Jerry Moran won the open seat. Kansas is one of the most Republican states in the nation; no Democrat has been elected to either Senate seat since 1932.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Lisa Johnston | 25,421 | 31.2% |
| | Democratic | Charles Schollenberger | 19,228 | 23.6% |
| | Democratic | David Haley | 15,584 | 19.2% |
| | Democratic | Patrick Wiesner | 13,359 | 16.4% |
| | Democratic | Robert Conroy | 7,779 | 9.6% |
| Total votes | Total votes | Total votes | 81,371 | 100.00% |
The retirement of Brownback, a popular U.S. Senator, led to a heavily competitive primary election. Tiahrt, who was on the Committee of Appropriations, had been accused of excessive earmarking while he was in Congress. From 2006 to 2008, Tiahrt had requested and supported a total of 63 solo earmarks, costing $53.9 million. In the same period, Moran had requested and supported a total of 29 earmarks, with a pricetag of $13.4 million.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Jerry Moran | 161,407 | 49.8% |
| | Republican | Todd Tiahrt | 144,372 | 44.6% |
| | Republican | Tom Little | 10,104 | 3.1% |
| | Republican | Bob Londerholm | 8,168 | 2.5% |
| Total votes | Total votes | Total votes | 324,051 | 100.00% |
After the primaries, Moran chose not to release any more negative advertisements. Democrat Lisa Johnston ran a low-profile, quiet race. On election day, she won only two counties: Wyandotte County and Douglas County, while Moran won statewide by a landslide.
2010 United States Senate election in Kansas :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Jerry Moran | 578,768 | 70.34% | +1.18% |
| | Democratic | Lisa Johnston | 215,270 | 26.16% | −1.33% |
| | Libertarian | Michael Dann | 17,437 | 2.12% | +0.18% |
| | Reform | Joe Bellis | 11,356 | 1.38% | −0.04% |
| Majority | Majority | Majority | 363,498 | 44.18% | |
| Total votes | Total votes | Total votes | 822,831 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Kentucky

Incumbent Republican Jim Bunning retired instead of seeking a third term. Republican nominee Rand Paul won the open seat.
On May 18, 2010, Paul won the Republican nomination. After conceding the election to Paul, Grayson said, "It's time to put all differences aside, unite behind Dr. Paul, he needs our help and I for one stand ready to serve".
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Rand Paul | 206,986 | 58.8% |
| | Republican | Trey Grayson | 124,864 | 35.4% |
| | Republican | Bill Johnson | 7,861 | 2.2% |
| | Republican | John Stephenson | 6,885 | 2.0% |
| | Republican | Gurley L. Martin | 2,850 | 0.8% |
| | Republican | Jon J. Scribner | 2,829 | 0.8% |
| Total votes | Total votes | Total votes | 352,275 | 100.0% |
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Jack Conway | 229,433 | 44.0% |
| | Democratic | Daniel Mongiardo | 225,260 | 43.2% |
| | Democratic | Darlene Fitzgerald Price | 28,531 | 5.5% |
| | Democratic | James Buckmaster | 20,561 | 3.9% |
| | Democratic | Maurice Sweeney | 17,874 | 3.4% |
| Total votes | Total votes | Total votes | 521,659 | 100.0% |
Grayson attacked Paul for his "strange ideas," such as his opposition of the PATRIOT Act, and what Grayson alleged to be his support of closing down Guantanamo Bay and saying that Iran was not a threat. He also attacked Paul for being a Duke University fan. He sent out another TV ad and web video that stirred controversy by making the case that Paul believes that foreign policy decisions made prior to September 11, 2001, are partially to blame for the attacks. Paul immediately responded by launching a statewide television ad in which he expresses his "outrage at terrorists who killed 3,000 innocents" before accusing Grayson of a "lie" and a "shameful" tactic. Grayson accused the Fox News Channel of favoring Paul over him.
Conway began the race trailing Paul, but as he attacked his opponent's positions on social-welfare and criminal-justice policies, the polls began to tighten. The campaign attracted $8.5 million in contributions from outside groups, of which $6 million was spent to help Rand Paul and $2.5 million to help Conway. This money influx was in addition to the money spent by the candidates themselves: $6 million by Paul and $4.7 million by Conway.
Kentucky election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Rand Paul | 755,411 | 55.69% | +5.03% |
| | Democratic | Jack Conway | 599,617 | 44.26% | −5.12% |
| Majority | Majority | Majority | 155,599 | 11.48% | |
| Total votes | Total votes | Total votes | 1,354,833 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Louisiana

Incumbent Republican David Vitter won re-election to a second term. Some speculated that Vitter's re-election might have become complicated, by the prostitution scandal revealed in 2007, but he continued to lead in aggregate polling against potential opponents.
Louisiana Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Charlie Melançon | 77,702 | 70.6% |
| | Democratic | Neeson Chauvin | 19,507 | 17.7% |
| | Democratic | Cary Deaton | 12,842 | 11.7% |
| Total votes | Total votes | Total votes | 110,051 | 100.0% |
Louisiana Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | David Vitter (Incumbent) | 85,179 | 87.6% |
| | Republican | Chet Traylor | 6,838 | 7.0% |
| | Republican | Nick Accardo | 5,221 | 5.4% |
| Total votes | Total votes | Total votes | 97,238 | 100.0% |
Melançon heavily criticized Vitter for prostitution sex scandal. Vitter released television advertising criticizing Melancon for his support for Obama's stimulus package and his support for amnesty for illegal immigrants. Melancon claimed "In August, Melancon challenged Vitter to a series of five live, televised town hall-style debates across the state. In his 2004 campaign for Senate, Vitter committed to five live, televised debates. Since Melancon issued the challenge, Vitter and Melancon have been invited to a total of seven live, televised debates. Vitter only accepted invitations to debates hosted by WWL-TV and WDSU-TV, both in New Orleans."
Louisiana election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | David Vitter (Incumbent) | 715,304 | 56.56% | +5.53% |
| | Democratic | Charlie Melancon | 476,423 | 37.67% | +8.44% |
| | Libertarian | Randall Hayes | 13,952 | 1.10% | N/A |
| | Independent | Michael Brown | 9,970 | 0.79% | N/A |
| | Independent | Mike Spears | 9,188 | 0.73% | N/A |
| | Independent | Ernest Wooton | 8,164 | 0.65% | N/A |
| | Independent | Skip Galan | 7,471 | 0.59% | N/A |
| | Reform | William McShan | 5,879 | 0.46% | N/A |
| | Independent | Bob Lang | 5,732 | 0.45% | N/A |
| | Independent | Milton Gordon | 4,806 | 0.38% | N/A |
| | Independent | Tommy LaFargue | 4,042 | 0.32% | N/A |
| | Independent | Sam Melton | 3,779 | 0.30% | N/A |
| Majority | Majority | Majority | 238,881 | 18.89% | |
| Total votes | Total votes | Total votes | 1,264,710 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Maryland

Incumbent Democrat Barbara Mikulski won re-election to a fifth term.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Barbara Mikulski (Incumbent) | 388,868 | 82.32% |
| | Democratic | Christopher J. Garner | 35,579 | 7.53% |
| | Democratic | A. Billy Bob Jaworski | 15,131 | 3.20% |
| | Democratic | Blaine Taylor | 10,787 | 2.28% |
| | Democratic | Theresa C. Scaldaferri | 7,913 | 1.68% |
| | Democratic | Sanquetta Taylor | 7,365 | 1.56% |
| | Democratic | Lih Young | 6,733 | 1.43% |
| Total votes | Total votes | Total votes | 472,376 | 100.00% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Eric Wargotz | 92,464 | 38.57% |
| | Republican | Jim Rutledge | 73,311 | 30.58% |
| | Republican | Joseph Alexander | 14,026 | 5.85% |
| | Republican | Neil H. Cohen | 13,613 | 5.68% |
| | Republican | Stephens Dempsey | 9,325 | 3.89% |
| | Republican | Daniel W. McAndrew | 8,460 | 3.53% |
| | Republican | John B. Kimble | 8,081 | 3.37% |
| | Republican | Samuel R. Graham, Sr. | 6,600 | 2.75% |
| | Republican | Barry Steve Asbury | 5,900 | 2.46% |
| | Republican | Eddie Vendetti | 5,046 | 2.10% |
| | Republican | Gregory Kump | 2,931 | 1.22% |
| Total votes | Total votes | Total votes | 239,757 | 100.00% |
Republican nominee Eric Wargotz, Queen Anne's County, Maryland Commission President and physician, compared Mikulski to a dinosaur by calling her a political "insidersaurus" for being in Washington for over thirty years An ad showed a hammer hitting a brick wall, breaking it down and citing criticisms of Mikulski's record as a U.S. Senator. Mikulski released advertisements emphasizing education and job creation. Despite Wargotz's limited campaign and resources he received the highest percentage of votes against Mikulski as an incumbent U.S. Senator
2010 United States Senate election in Maryland :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Barbara Mikulski (Incumbent) | 1,140,531 | 62.19% | −2.61% |
| | Republican | Eric Wargotz | 655,666 | 35.75% | +2.05% |
| | Green | Kenniss Henry | 20,717 | 1.13% | +0.06% |
| | Constitution | Richard Shawver | 14,746 | 0.80% | +0.42% |
| | Write-ins | | 2,213 | 0.11% | +0.05% |
| Majority | Majority | Majority | 484,865 | 26.44% | |
| Total votes | Total votes | Total votes | 1,833,873 | 100.00% | |
| | Democratic hold | Democratic hold | Swing | | |

## Massachusetts (special)

A special election was held January 19, 2010 to fill the Class 1 seat for the remainder of the term ending January 3, 2013. It was won by Republican Scott Brown.
Incumbent Democrat Ted Kennedy had died on August 25, 2009. Governor of Massachusetts appointed Democrat Paul Kirk September 24, 2009, to continue the term pending this special election, in which Kirk was not a candidate.
The election was viewed by conservatives outside of Massachusetts as a referendum on President Barack Obama. However, Brown stated that he didn't believe that it was a referendum on Obama. Although Democrats would retain control of both Houses of Congress until January 2011, Brown's victory greatly affected their political plans, most notably for the Patient Protection and Affordable Care Act, though the legislation was signed into law two months later. Brown became the first Republican to win this seat since 1946, and as of 2025, this is the last Senate election in Massachusetts won by a Republican.
Massachusetts Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Martha Coakley | 310,227 | 47% |
| | Democratic | Mike Capuano | 184,791 | 28% |
| | Democratic | Alan Khazei | 88,929 | 13% |
| | Democratic | Stephen Pagliuca | 80,248 | 12% |
| Total votes | Total votes | Total votes | 664,195 | 100% |
Massachusetts Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Scott Brown | 145,465 | 89% |
| | Republican | Jack Robinson | 17,241 | 11% |
| Total votes | Total votes | Total votes | 162,706 | 100% |
Massachusetts special election :
| Party | Party | Candidate | Votes | % |
| | Republican | Scott Brown | 1,168,178 | 51.83% |
| | Democratic | Martha Coakley | 1,060,861 | 47.07% |
| | Libertarian | Joseph L. Kennedy | 22,388 | 0.99% |
| | | All others | 1,155 | 0.05% |
| | | Blanks | 1,145 | 0.05% |
| Total votes | Total votes | Total votes | 2,253,727 | 100% |
| Turnout | Turnout | Turnout | | 54% |
| | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic |

## Missouri

Incumbent Republican Kit Bond retired instead of seeking a fifth term. Republican nominee Roy Blunt won the open seat.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Roy Blunt | 411,040 | 70.9% |
| | Republican | Chuck Purgason | 75,663 | 13.1% |
| | Republican | Kristi Nichols | 40,744 | 7.0% |
| | Republican | Deborah Solomon | 15,099 | 2.6% |
| | Republican | Hector Maldonado | 8,731 | 1.5% |
| | Republican | Davis Conway | 8,525 | 1.5% |
| | Republican | R.L. Praprotnik | 8,047 | 1.4% |
| | Republican | Tony Laszacs | 6,309 | 1.1% |
| | Republican | Mike Vontz | 5,190 | 0.9% |
| Total votes | Total votes | Total votes | 579,348 | 100.00% |
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Robin Carnahan | 266,349 | 83.9% |
| | Democratic | Richard Charles Tolbert | 33,731 | 10.6% |
| | Democratic | Francis Vangeli | 17,511 | 5.5% |
| Total votes | Total votes | Total votes | 317,591 | 100.00% |
Democrat Robin Carnahan and national Democrats heavily criticized Blunt for his support of bailouts, calling him "Bailout Blunt." Blunt criticized her for supporting President Obama's stimulus package, the cap-and-trade energy bill, and the health care reform bill.
2010 United States Senate election in Missouri :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Roy Blunt | 1,054,160 | 54.23% | −1.86% |
| | Democratic | Robin Carnahan | 789,736 | 40.63% | −2.17% |
| | Libertarian | Jonathan Dine | 58,663 | 3.02% | +2.29% |
| | Constitution | Jerry Beck | 41,309 | 2.13% | +1.74% |
| Majority | Majority | Majority | 264,424 | 13.60% | |
| Total votes | Total votes | Total votes | 1,943,868 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Nevada

Incumbent Democratic Majority Leader Harry Reid won re-election to a fifth term.
Democratic primary Tuesday, June 8, 2010 :
| Party | Party | Candidate | Votes | % |
| | Democratic | Harry Reid (Incumbent) | 87,401 | 75.3% |
| | Democratic | None of these | 12,341 | 10.6% |
| | Democratic | Alex Miller | 9,717 | 8.4% |
| | Democratic | Eduardo Hamilton | 4,645 | 4.0% |
| | Democratic | Carlo Poliak | 1,938 | 1.7% |
| Total votes | Total votes | Total votes | 116,042 | 100.00% |
Republican primary Tuesday, June 8, 2010 :
| Party | Party | Candidate | Votes | % |
| | Republican | Sharron Angle | 70,452 | 40.1% |
| | Republican | Sue Lowden | 45,890 | 26.1% |
| | Republican | Danny Tarkanian | 40,936 | 23.3% |
| | Republican | John Chachas | 6,926 | 3.9% |
| | Republican | Chad Christensen | 4,806 | 2.7% |
| | Republican | None of these | 3,091 | 1.8% |
| | Republican | Bill Parson | 1,484 | 0.8% |
| | Republican | Gary Bernstein | 698 | 0.4% |
| | Republican | Garn Mabey | 462 | 0.3% |
| | Republican | Cecilia Stern | 355 | 0.2% |
| | Republican | Brian Nadell | 235 | 0.1% |
| | Republican | Terry Suominen | 224 | 0.1% |
| | Republican | Gary Marinch | 179 | 0.1% |
| Total votes | Total votes | Total votes | 175,738 | 100.00% |
Reid was initially considered vulnerable, with the non-partisan Cook Political Report rating the election as a toss-up and the Rothenberg Political Report rating the state as toss-up. A June 9, 2010, Rasmussen Reports post-primary poll showed Angle leading incumbent Senator Harry Reid by a margin of 50% to 39%. However, a July 2010 poll showed Senator Reid leading Angle by 7 points, following nationwide attention to some of Angle's positions, as well as the endorsement of Reid by prominent Republicans. The change of margin, 18% in less than a month, is the largest in Senate elections history. On July 28, 2010, Rasmussen Reports moved the race from toss-up to leans Democratic. Later, it moved back to toss-up. Despite Angle leading by three points in the polls the days leading up to the election, Reid defeated her by 5.74%, even in her own county, Washoe County. Reid also secured huge numbers out of the Democratic stronghold of Clark County, which covers the Las Vegas Metropolitan Area. Angle's far right beliefs and positions were also widely cited as a reason for the failure of the Republican Party defeating Reid.
2010 United States Senate election in Nevada :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Harry Reid (Incumbent) | 362,785 | 50.29% | −10.84% |
| | Republican | Sharron Angle | 321,361 | 44.55% | +9.45% |
| | None of These Candidates | – | 16,174 | 2.25% | +0.65% |
| | Tea Party | Scott Ashjian | 5,811 | 0.81% | N/A |
| | Independent | Michael L. Haines | 4,261 | 0.59% | N/A |
| | Independent American Party (Nevada) | Timothy Fasano | 3,185 | 0.44% | N/A |
| | Independent | Jesse Holland | 3,175 | 0.44% | N/A |
| | Independent | Jeffery C. Reeves | 2,510 | 0.35% | N/A |
| | Independent | Wil Stand | 2,119 | 0.29% | N/A |
| Majority | Majority | Majority | 41,424 | 5.74% | |
| Total votes | Total votes | Total votes | 721,381 | 100.00% | -11.14% |
| | Democratic hold | Democratic hold | Swing | | |

## New Hampshire

Incumbent Republican Judd Gregg retired instead of seeking a fourth term. Republican nominee Kelly Ayotte won the open seat by over 23 points, after winning a close party primary. New Hampshire trended Democratic in the 2006 and 2008 elections, with Republican incumbents losing both of the state's House seats and its other Senate seat to Democrats, but polling conducted in late December 2008 showed Gregg defeating both of the state's U.S. Representatives in a hypothetical match-up.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Kelly Ayotte | 53,056 | 38.21% |
| | Republican | Ovide Lamontagne | 51,397 | 37.01% |
| | Republican | Bill Binnie | 19,508 | 14.05% |
| | Republican | Jim Bender | 12,611 | 9.08% |
| | Republican | Dennis Lamare | 1,388 | 1.00% |
| | Republican | Tom Alciere | 499 | 0.36% |
| | Republican | Gerard Beloin | 402 | 0.29% |
| Total votes | Total votes | Total votes | 138,861 | 100.00% |
Democrat Paul Hodes called himself a fiscal conservative, which was mocked by Republican Kelly Ayotte in a TV ad. Hodes was criticized for supporting President Obama's Economic Recovery package, a carbon energy tax, and Affordable Care Act. Hodes criticized Ayotte for numerous controversies. One ad was questioned Ayotte's honesty in dealing with the Lakes Region Ponzi scheme which defrauded investors of almost $80 million.
New Hampshire election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Kelly Ayotte | 272,703 | 60.16% | −6.08% |
| | Democratic | Paul Hodes | 166,538 | 36.74% | +2.99% |
| | Independent | Chris Booth | 9,285 | 2.05% | N/A |
| | Libertarian | Ken Blevens | 4,754 | 1.05% | +1.03% |
| Majority | Majority | Majority | 106,165 | 23.42% | |
| Total votes | Total votes | Total votes | 453,280 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## New York

There were two elections, due to the resignation of Hillary Clinton in January 2009 to become the U.S. Secretary of State. Both senate races, along with the New York gubernatorial election, one with a vulnerable Democratic incumbent and the other an open race, respectively, was believed to lead major New York Republicans to gravitate towards them rather than challenge the popular Schumer. As it happened, however, New York Republicans had difficulty drawing top-tier candidates to any of the three races.

### New York (regular)

Incumbent Democrat Chuck Schumer won re-election to a third term.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Jay Townsend | 234,440 | 55.41% |
| | Republican | Gary Berntsen | 188,628 | 44.59% |
| Total votes | Total votes | Total votes | 423,068 | 100.00% |
New York regular election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Chuck Schumer (Incumbent) | 2,686,043 | 56.27% |
| | Working Families | Chuck Schumer (Incumbent) | 183,672 | 3.85% |
| | Independence | Chuck Schumer (Incumbent) | 177,396 | 3.72% |
| | Total | Chuck Schumer (Incumbent) | 3,047,111 | 63.84% |
| | Republican | Jay Townsend | 1,238,947 | 25.96% |
| | Conservative | Jay Townsend | 240,777 | 5.04% |
| | Total | Jay Townsend | 1,479,724 | 31.00% |
| | Green | Colia Clark | 42,340 | 0.89% |
| | Libertarian | Randy Credico | 24,863 | 0.52% |
| | None | Blank/Void/Scattering | 179,373 | 3.76% |
| Total votes | Total votes | Total votes | 4,773,411 | 100.0% |
| | Democratic hold | Democratic hold | Democratic hold | Democratic hold |

### New York (special)

Governor David Paterson had appointed Democrat Kirsten Gillibrand to serve as United States Senator this special election, replacing former Senator Hillary Clinton, who resigned to serve as U.S. Secretary of State in the Barack Obama administration. The winner of the special election would complete the term ending in January 2013. Due to this special election, this was the first time since the ratification of the 17th Amendment in 1913 that all of New York's six statewide offices were up for popular election on the same date.
Gillibrand claimed to be an independent thinker who took a back seat to no one. She also released television advertising touting her background from upstate New York while DioGuardi criticized Gillibrand's appearance in Vogue magazine.
New York Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Kirsten Gillibrand (Incumbent) | 464,512 | 76.1% |
| | Democratic | Gail Goode | 145,491 | 23.9% |
| Total votes | Total votes | Total votes | 610,003 | 100.00% |
New York Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Joseph DioGuardi | 185,483 | 41.8% |
| | Republican | David Malpass | 167,151 | 37.7% |
| | Republican | Bruce Blakeman | 91,312 | 20.5% |
| Total votes | Total votes | Total votes | 443,946 | 100.0% |
New York general election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Kirsten Gillibrand (Incumbent) | 2,479,393 | |
| | Working Families | Kirsten Gillibrand | 182,655 | |
| | Independence | Kirsten Gillibrand | 175,636 | |
| | Total | Kirsten Gillibrand (Incumbent) | 2,837,684 | 59.64% |
| | Republican | Joe DioGuardi | 1,338,308 | |
| | Conservative | Joe DioGuardi | 244,385 | |
| | Total | Joe DioGuardi | 1,582,693 | 33.27% |
| | Green | Cecile A. Lawrence | 35,489 | 0.75% |
| | Libertarian | John Clifton | 18,414 | 0.39% |
| | Rent Is Too Damn High | Joseph Huff | 17,019 | 0.36% |
| | Anti-Prohibition | Vivia Morgan | 11,787 | 0.25% |
| | Tax Revolt | Bruce Blakeman | 4,516 | 0.09% |
| | None | Blank, Void, and Scattered | 250,033 | 5.26% |
| Majority | Majority | 1,254,991 | 26.38% | |
| Turnout | Turnout | 4,757,635 | | |
| | Democratic hold | Democratic hold | Democratic hold | Democratic hold |

## North Carolina

Incumbent Republican Richard Burr won re-election to a second term. Burr was the first incumbent to win re-election for this seat since Sam Ervin's last re-election in 1968. Burr's 54.8% also represented the highest vote share a North Carolina Republican received since the state began directly electing its senators.
This Senate seat was unfavorable to incumbents over the past several decades. No person elected to this seat was re-elected since Sam Ervin in 1968. His successor, Democrat Robert Burren Morgan, was defeated for re-election in 1980, along with many other incumbents from his party. His Republican successor, John Porter East, committed suicide in 1986. East's appointed successor, Jim Broyhill, served for just four months, resigning upon his November 1986 election loss to former Democratic Governor Terry Sanford. In 1992, the seat changed hands yet again, as Sanford was defeated by wealthy GOP businessman Lauch Faircloth, who himself lost in his bid for a second term six years later by John Edwards. In 2004, no incumbent was defeated, as Edwards was running for vice president and was not allowed to be on the ballot in both races. However, that year the seat did change parties for the fifth time in a row, with Richard Burr defeating Bill Clinton's onetime Chief of Staff Erskine Bowles.
Democratic primary election - May 4, 2010* :
| Party | Party | Candidate | Votes | % |
| | Democratic | Elaine Marshall | 154,605 | 36.4% |
| | Democratic | Cal Cunningham | 115,851 | 27.3% |
| | Democratic | Ken Lewis | 72,510 | 17.1% |
| | Democratic | Marcus W. Williams | 35,984 | 8.5% |
| | Democratic | Susan Harris | 29,738 | 7.0% |
| | Democratic | Ann Worthy | 16,655 | 3.9% |
| Total votes | Total votes | Total votes | 425,343 | 100.0% |
* Note: Since no candidate received 40% of the vote on May 4, state law allowed a runoff (or "second primary") election if requested by the second-place finisher. Cunningham requested such a runoff.
Democratic primary election runoff (June 22, 2010) :
| Party | Party | Candidate | Votes | % |
| | Democratic | Elaine Marshall | 95,390 | 60.0% |
| | Democratic | Cal Cunningham | 63,691 | 40.0% |
| Total votes | Total votes | Total votes | 159,081 | 100.0% |
Republican primary election - May 4, 2010 :
| Party | Party | Candidate | Votes | % |
| | Republican | Richard Burr (Incumbent) | 297,993 | 80.1% |
| | Republican | Brad Jones | 37,616 | 10.1% |
| | Republican | Eddie Burks | 22,111 | 5.9% |
| | Republican | Larry Linney | 14,248 | 3.8% |
| Total votes | Total votes | Total votes | 371,968 | 100.0% |
2010 United States Senate election in North Carolina :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Richard Burr (Incumbent) | 1,458,046 | 54.81% | +3.21% |
| | Democratic | Elaine Marshall | 1,145,074 | 43.05% | −3.97% |
| | Libertarian | Mike Beitler | 55,682 | 2.09% | +0.72% |
| Majority | Majority | Majority | 312,972 | 11.76% | |
| Total votes | Total votes | Total votes | 2,660,079 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## North Dakota

Incumbent Democrat Byron Dorgan did not seek re-election. Republican Governor John Hoeven won the open seat. Incumbent Byron Dorgan never had a difficult time getting elected, as he obtained 59%, 63%, and 68% in his three senate election bids, respectively. However, in December 2009, Rasmussen Reports conducted a hypothetical matchup of Governor John Hoeven against the incumbent. Hoeven led by a large margin, 58% to Dorgan's 36%. 61% of the state still had a favorable view of Dorgan, and if pitted against State Senator Duane Sand, the incumbent led 52% to 37%.
Hoeven was challenged in the race by North Dakota State Senator Tracy Potter of Bismarck. Potter received the endorsement of the North Dakota Democratic-NPL Party at its state convention on March 27, 2010. Governor Hoeven and Senator Potter advanced to the November 2, 2010 general election following balloting in North Dakota's primary election, which was held June 8, 2010. Neither candidate faced any significant opposition in the primary election.
Democratic-NPL primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic–NPL | Tracy Potter | 26,211 | 99.6% |
| | Democratic–NPL | Write-ins | 95 | 0.4% |
| Total votes | Total votes | Total votes | 26,306 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | John Hoeven | 64,978 | 99.8% |
| | Republican | Timothy Beattie | 130 | 0.2% |
| Total votes | Total votes | Total votes | 65,108 | 100.0% |
North Dakota election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | John Hoeven | 181,689 | 76.08% | +44.36% |
| | Democratic–NPL | Tracy Potter | 52,955 | 22.17% | −46.11% |
| | Libertarian | Keith Hanson | 3,890 | 1.63% | N/A |
| Majority | Majority | Majority | 128,734 | 53.91% | |
| Turnout | Turnout | Turnout | 238,534 | 100.00% | |
| | Republican gain from Democratic–NPL | Republican gain from Democratic–NPL | Swing | | |

## Ohio

Incumbent Republican George Voinovich retired instead of seeking a third term. Republican former Director of the Office of Management and Budget, United States Trade Representative, and Congressman Rob Portman won the open seat.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Lee Irwin Fisher | 380,189 | 55.6% |
| | Democratic | Jennifer Lee Brunner | 304,026 | 44.4% |
| Total votes | Total votes | Total votes | 684,206 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Rob Portman | 667,369 | 100.00% |
| Total votes | Total votes | Total votes | 657,354 | 100.00% |
Originally, the election was seen as a toss-up. His experience as a former Bush official was considered to be a big problem for Portman. Both President Barack Obama and Vice President Joe Biden campaigned for Fisher. Television advertisements were very negative. Fisher attacked Portman for helping to ship jobs overseas during his entire political career, backing deals that shipped jobs overseas, and the trade deficit with China, which grew by over $41 billion. Portman claimed in response that most jobs were being lost to other states, not countries. Portman attacked Fisher for supporting Obama's stimulus and cap and trade.
Winning the election, Portman received the majority of votes in 82 of 88 counties and in 15 of 18 Congressional districts, including the district of liberal U.S. Congressman Dennis Kucinich.
2010 United States Senate election in Ohio :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Robert Jones Portman | 2,168,742 | 56.85% | −6.61% |
| | Democratic | Lee Irwin Fisher | 1,503,297 | 39.40% | +2.85% |
| | Constitution | Eric Deaton | 65,856 | 1.72% | N/A |
| | Independent | Michael Pryce | 50,101 | 1.31% | N/A |
| | Socialist | Daniel LaBotz | 26,454 | 0.69% | N/A |
| | N/A | Arthur Sullivan (write-in) | 648 | 0.02% | N/A |
| Majority | Majority | Majority | 665,445 | 17.44% | |
| Total votes | Total votes | Total votes | 3,815,098 | 100.00% | |
| | Republican hold | Republican hold | Swing | NA | |

## Oklahoma

Incumbent first-term Republican Tom Coburn won re-election to a second term. Coburn, a very popular incumbent, promised to limit himself to two terms. Despite his popularity, he did release television advertisements. In 2009, Coburn's approval rating in a PPP poll was 59%, including a 39% approval rating among Democrats. His Democratic opponent is a perennial candidate who did little campaigning.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Jim Rogers | 157,955 | 65.4% |
| | Democratic | Mark Myles | 83,715 | 34.6% |
| Total votes | Total votes | Total votes | 241,670 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Tom Coburn (Incumbent) | 223,997 | 90.4% |
| | Republican | Evelyn Rogers | 15,093 | 6.1% |
| | Republican | Lewis Kelly Spring | 8,812 | 3.5% |
| Total votes | Total votes | Total votes | 247,902 | 100.00% |
Oklahoma election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Tom Coburn (Incumbent) | 718,482 | 70.64% | +17.87% |
| | Democratic | Jim Rogers | 265,814 | 26.13% | −15.11% |
| | Independent | Stephen Wallace | 25,048 | 2.46% | N/A |
| | Independent | Ronald F. Dwyer | 7,807 | 0.77% | N/A |
| Majority | Majority | Majority | 452,668 | 44.50% | |
| Total votes | Total votes | Total votes | 1,017,151 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Oregon

Incumbent Democrat Ron Wyden won re-election to a third full term. Wyden, a popular incumbent with a 52% approval rating in a July poll, touted bipartisanship and promised to hold town-hall meetings annually in each of Oregon's 36 counties and to open offices outside of Portland and Salem. A Survey USA poll taken a few days before the election showed that 23% of Republicans supported Wyden.
Huffman, widely considered as an underdog, financed his own campaign. He defended bonuses for Wall Street executives and questioned global warming.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Ron Wyden (incumbent) | 323,652 | 89.55% |
| | Democratic | Loren Hooker | 25,152 | 6.75% |
| | Democratic | Pavel Goberman | 9,985 | 2.68% |
| | Democratic | Write-ins | 3,782 | 1.02% |
| Total votes | Total votes | Total votes | 376,353 | 100.00% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Jim Huffman | 110,450 | 41.70% |
| | Republican | Loren Later | 39,753 | 15.01% |
| | Republican | G. Shane Dinkel | 36,760 | 13.88% |
| | Republican | Thomas Stutzman | 31,859 | 12.03% |
| | Republican | Keith Waldron | 24,602 | 9.29% |
| | Republican | Robin Parker | 14,637 | 5.53% |
| | Republican | Walter Woodland | 4,417 | 1.67% |
| | Republican | Write-ins | 2,213 | 0.86% |
| Total votes | Total votes | Total votes | 267,054 | 100% |
Oregon election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Ron Wyden (Incumbent) | 825,507 | 57.22% |
| | Republican | Jim Huffman | 566,199 | 39.25% |
| | Working Families | Bruce Cronk | 18,940 | 1.31% |
| | Libertarian | Marc Delphine | 16,028 | 1.11% |
| | Progressive | Rick Staggenborg | 14,466 | 1.00% |
| | Write-In | | 1,448 | 0.10% |
| Total votes | Total votes | Total votes | 1,442,588 | 100.0% |
| | Democratic hold | Democratic hold | Democratic hold | Democratic hold |

## Pennsylvania

Incumbent Republican-turned-Democrat Arlen Specter ran for re-election to a sixth term, but he lost in the Democratic primary to Joe Sestak. Republican nominee Pat Toomey then won the seat.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Joe Sestak | 568,563 | 53.9% |
| | Democratic | Arlen Specter (Incumbent) | 487,217 | 46.1% |
| Total votes | Total votes | Total votes | 1,055,780 | 100.00% |
Pennsylvania election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Pat Toomey | 2,028,945 | 51.01% | −1.61% |
| | Democratic | Joe Sestak | 1,948,716 | 48.99% | +7.00% |
| Majority | Majority | Majority | 80,229 | 2.02% | |
| Total votes | Total votes | Total votes | 3,977,661 | 100.00% | |
| | Republican gain from Democratic | Republican gain from Democratic | Swing | | |

## South Carolina

Incumbent Republican Jim DeMint won re-election to a second term. Alvin Greene, the Democratic nominee, was the first major-party African-American U.S. Senate candidate in South Carolina since Reconstruction. Alvin Greene's Democratic primary election win and his margin of victory surprised pundits. As of the primary, he had held no public campaign events, raised no money, and did not have a campaign website. A review of the primary election showed that of the state's 46 counties, half had a significant gap between the absentee and primary day ballots. For example, in Lancaster County, Vic Rawl won the absentees with 84 percent, while Greene won primary day by a double-digit margin. Rawl's campaign manager also claimed, "In only two of 88 precincts, do the number of votes Greene got plus the number we got equal the total cast."
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Alvin Greene | 100,362 | 59.0% |
| | Democratic | Vic Rawl | 69,853 | 41.0% |
| Total votes | Total votes | Total votes | 170,215 | 100.0% |
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Jim DeMint (Incumbent) | 342,464 | 83.0% |
| | Republican | Susan McDonald Gaddy | 70,194 | 17.0% |
| Total votes | Total votes | Total votes | 412,658 | 100.0% |
2010 United States Senate election in South Carolina :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Jim DeMint (Incumbent) | 810,771 | 61.48% | +7.81% |
| | Democratic | Alvin Greene | 364,598 | 27.65% | −16.46% |
| | Green | Tom Clements | 121,472 | 9.21% | +8.95% |
| | | Write-ins | 21,953 | 1.66% | +1.58% |
| Majority | Majority | Majority | 446,173 | 33.83% | +24.33% |
| Total votes | Total votes | Total votes | 1,318,794 | 50.12% | -18.88% |
| | Republican hold | Republican hold | Swing | | |

## South Dakota

Incumbent Republican John Thune won re-election to a second term unopposed.
Thune was narrowly elected to his first term over Democratic Senate Minority Leader Tom Daschle with 51% of the vote in 2004. In spite of his lack of seniority, Thune rose to the position of chairman of the Republican Policy Committee in the United States Senate.
No members of the South Dakota Democratic Party (or any other party) filed to challenge Thune. Scott Heidepriem, the South Dakota Senate Minority Leader and a Democratic candidate for Governor of South Dakota, said, "We just concluded that John Thune is an extremely popular senator who is going to win another term in the Senate."

## Utah

Incumbent Republican Bob Bennett was seeking re-election to a fourth term, but was eliminated in the GOP state convention. Republican Mike Lee, who won the Republican primary, won the open seat.
At the Republican convention, incumbent Senator Bob Bennett finished third in balloting among delegates and was eliminated from the race. Business owner Tim Bridgewater finished first and attorney Mike Lee finished second, but Bridgewater did not receive enough votes to avoid a primary election runoff against Lee. At the Democratic convention, delegates nominated businessman Sam Granato, who received 77.5 percent of the vote.
Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Mike Lee | 98,512 | 51.2% |
| | Republican | Tim Bridgewater | 93,905 | 48.8% |
| Total votes | Total votes | Total votes | 192,417 | 100.0% |
Democratic convention :
| Party | Party | Candidate | Votes | % |
| | Democratic | Sam Granato | 77 | 77.5% |
| | Democratic | Christopher Stout | 23 | 22.5% |
| Total votes | Total votes | Total votes | 100 | 100.0% |
Utah election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Mike Lee | 390,179 | 61.56% | −7.18% |
| | Democratic | Sam Granato | 207,685 | 32.77% | +4.37% |
| | Constitution | Scott Bradley | 35,937 | 5.67% | +3.78% |
| Majority | Majority | Majority | 182,494 | 28.79% | |
| Total votes | Total votes | Total votes | 633,801 | 100.00% | |
| | Republican hold | Republican hold | Swing | | |

## Vermont

Incumbent Democrat Patrick Leahy easily won re-election to a seventh term.
Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Patrick Leahy (Incumbent) | 64,177 | 89.06% |
| | Democratic | Daniel Frielich | 7,886 | 10.94% |
| Total votes | Total votes | Total votes | 72,063 | 100.0% |
2010 United States Senate election in Vermont :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Patrick Leahy (Incumbent) | 151,281 | 64.36% | −6.27% |
| | Republican | Len Britton | 72,699 | 30.93% | +6.38% |
| | Independent | Daniel Freilich | 3,544 | 1.51% | N/A |
| | Marijuana | Cris Ericson | 2,731 | 1.16% | N/A |
| | Independent | Stephen Cain | 2,356 | 1.00% | N/A |
| | Socialist | Peter Diamondstone | 1,433 | 0.61% | N/A |
| | Independent | Johenry Nunes | 1,021 | 0.43% | N/A |
| Majority | Majority | Majority | 78,528 | 33.43% | |
| Total votes | Total votes | Total votes | 235,065 | 100.00% | |
| | Democratic hold | Democratic hold | Swing | | |

## Washington

Incumbent Democrat Patty Murray won re-election to a fourth term.
Republican Dino Rossi heavily criticized Murray for her support of the 2009 economic stimulus package; however, Rossi's economic promises are nearly identical to those of President Bush who asked for the stimulus. Rossi supports repealing the Patient Protection and Affordable Care Act and the Dodd-Frank Wall Street Reform and Consumer Protection Act. He also criticized Murray for her support for earmarks. In response, Murray said, "You bet that seniority and leadership has a big thing to do with it, but the other part of it is, I get up every day and I work hard and I believe in this and I am going to continue fighting for the community I represent."
Washington Blanket primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Patty Murray (Incumbent) | 670,284 | 46.22% |
| | Republican | Dino Rossi | 483,305 | 33.33% |
| | Republican | Clint Didier | 185,034 | 12.76% |
| | Republican | Paul Akers | 37,231 | 2.57% |
| | Independent | Skip Mercer | 12,122 | 0.84% |
| | Democratic | Charles Allen | 11,525 | 0.79% |
| | Democratic | Bob Burr | 11,344 | 0.78% |
| | Republican | Norma Gruber | 9,162 | 0.63% |
| | Republican | Michael Latimer | 6,545 | 0.45% |
| | Democratic | Mike the Mover | 6,019 | 0.42% |
| | Democratic | Goodspaceguy | 4,718 | 0.33% |
| | Reform | William Baker | 4,593 | 0.32% |
| | Independent | Mohammad Said | 3,387 | 0.23% |
| | Independent | Schalk Leonard | 2,818 | 0.19% |
| | Republican | William Chovil | 2,039 | 0.14% |
| Total votes | Total votes | Total votes | 1,450,126 | 100.00% |
Washington General election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Patty Murray (Incumbent) | 1,314,930 | 52.36% |
| | Republican | Dino Rossi | 1,196,164 | 47.64% |
| Total votes | Total votes | Total votes | 2,511,094 | 100.00% |
| Turnout | Turnout | Turnout | | 71.24% |

## West Virginia (special)

Long-time Democratic Senator Robert Byrd died June 28, 2010, and Democratic Governor Joe Manchin appointed Carte Goodwin to temporarily fill the vacancy. Goodwin pledged to not run for election to the seat in exchange for the appointment. Manchin won the open seat and served out the remainder of Byrd's elected term, which ended on January 3, 2013.
During the Republican primary campaign, only Raese and Warner released television advertisements.
West Virginia Democratic primary election :
| Party | Party | Candidate | Votes | % |
| | Democratic | Joe Manchin | 67,498 | 72.9% |
| | Democratic | Ken Hechler | 16,039 | 17.3% |
| | Democratic | Sheirl Fletcher | 9,035 | 9.8% |
| Total votes | Total votes | Total votes | 92,572 | 100% |
West Virginia Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | John Raese | 38,152 | 71.4% |
| | Republican | Mac Warner | 7,892 | 14.8% |
| | Republican | Scott H. Williams | 1,530 | 2.9% |
| | Republican | Kenneth Culp | 1,364 | 2.6% |
| | Republican | Harry C. Bruner Jr. | 1,283 | 2.4% |
| | Republican | Thomas Ressler | 1,184 | 2.2% |
| | Republican | Lynette Kennedy McQuain | 907 | 1.7% |
| | Republican | Frank Kubic | 462 | 0.9% |
| | Republican | Daniel Scott Rebich | 450 | 0.8% |
| | Republican | Albert Howard | 176 | 0.3% |
| Total votes | Total votes | Total votes | 53,400 | 100% |
2010 United States Senate special election in West Virginiaresults :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Joe Manchin | 283,358 | 53.47% | −10.96% |
| | Republican | John Raese | 230,013 | 43.40% | +9.69% |
| | Mountain | Jesse Johnson | 10,152 | 1.92% | +0.06% |
| | Constitution | Jeff Becker | 6,425 | 1.21% | N/A |
| Majority | Majority | Majority | 53,345 | 10.07% | |
| Total votes | Total votes | Total votes | 529,948 | 100% | |
| | Democratic hold | Democratic hold | Swing | | |

## Wisconsin

Incumbent Democrat Russ Feingold ran for re-election to a fourth term, but was defeated by political newcomer, Republican Ron Johnson. Johnson, a millionaire manufacturer and Tea Party movement favorite who was running for his first political office, was the front runner. In response to controversy over his ownership of stock in BP, Johnson said he would sell it when market conditions were favorable and possibly use the proceeds to help finance his Senate campaign. Feingold's first television ad was a positive ad released in March. In July 2010, Feingold's second 2010 television election ad attacked Johnson for alleged support for offshore drilling in the Great Lakes. Johnson quickly countered Feingold with a television ad of his own. Feingold's logo was Moving Forward. In one ad he emphasized independence and called himself a "Penny Pincher." Johnson argued that his professions, manufacturer and accountant were underrepresented in the U.S. Senate, and there were too many lawyers (57 out of 100 members), including Feingold.
Wisconsin Republican primary election :
| Party | Party | Candidate | Votes | % |
| | Republican | Ron Johnson | 500,821 | 84.7% |
| | Republican | David Westlake | 61,287 | 10.4% |
| | Republican | Stephen M. Finn | 29,002 | 4.9% |
| Total votes | Total votes | Total votes | 591,107 | 100.0% |
Wisconsin election :
| Party | Party | Candidate | Votes | % | ±% |
| | Republican | Ron Johnson | 1,125,999 | 51.86% | +7.75% |
| | Democratic | Russ Feingold (Incumbent) | 1,020,958 | 47.02% | −8.33% |
| | Constitution | Rob Taylor | 23,473 | 1.08% | N/A |
| | | Write-In Votes | 901 | 0.04% | N/A |
| Majority | Majority | Majority | 105,041 | 4.84% | −6.4% |
| Turnout | Turnout | Turnout | 2,170,430 | 100.00% | −26.4% |
| | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic | Republican gain from Democratic |