# 2018 United States Senate election in Arizona

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vte :
The 2018 United States Senate election in Arizona took place on November 6, 2018. Incumbent Republican Senator Jeff Flake did not seek a second term. The election was held concurrently with a gubernatorial election, other elections to the U.S. Senate, elections to the U.S. House of Representatives, and various other state and local elections.
Primaries were held on August 28, 2018, three days after the death of longtime U.S. Senator John McCain. Martha McSally won the Republican nomination, while Kyrsten Sinema won the Democratic nomination. Green Party candidate Angela Green was also on the ballot, but ended her campaign and endorsed Sinema before Election Day.
The Associated Press called the race for Sinema on November 12, 2018, and McSally conceded that day. Sinema became the first Democrat to win a U.S. Senate seat in Arizona since 1988. McSally was subsequently appointed by Governor Doug Ducey to the other vacant Senate seat in Arizona, left open after McCain's death and then held on an interim basis by Jon Kyl.

## Background

Arizona, located along the United States border with Mexico, has a unique political history. Upon its admission to the Union in 1912, the state was dominated by Democrats who had migrated there from the South, and aside from the landslide victories of Republicans Warren G. Harding, Calvin Coolidge, and Herbert Hoover, the state voted for Democrats until 1952, when Dwight Eisenhower carried it, and began a lengthy streak of Republican victories interrupted only by Bill Clinton's narrow victory in 1996. Since then, the state had remained Republican, and was won by Donald Trump with a 3.5% margin in 2016, although Trump's margin of victory was much smaller than that of past Republican presidential nominees.
Incumbent Republican Senator Jeff Flake announced in October 2017 that he would retire at the end of his current term instead of seeking reelection for another term in 2018. Flake had previously indicated his intent to run for reelection in March 2017. However, he was considered vulnerable due to persistently low approval ratings, a poor relationship with President Trump, and the threat of a primary challenge from former state senator Kelli Ward, who promised to run on a more pro-Trump platform. Additionally, he had won his first term in 2012 by only 3 percentage points, even though Republican presidential nominee Mitt Romney won Arizona by 9.

## Republican primary
### Candidates
#### On the ballot

* Joe Arpaio, former Maricopa County sheriff
* Nicholas N. Glenn (write-in candidate)
* William Gonzales (write-in candidate)
* Martha McSally, U.S. representative and retired U.S. Air Force Colonel
* Kelli Ward, former state senator and candidate for the U.S. Senate in 2016

#### Failed to file

* Craig Brittain, owner and co-founder of the revenge porn website IsAnybodyDown?
* Christian "C.J." Diegel, financial advisor
* Michelle Griffin
* Shawn Redd
* Nicholas Tutora, pharmacist

#### Withdrew

* Jeff Flake, incumbent U.S. senator

#### Declined

* Andy Biggs, U.S. representative from Arizona's 5th congressional district
* Jan Brewer, former governor of Arizona
* Mark Brnovich, attorney general of Arizona
* Jeff DeWit, treasurer of Arizona (nominated as NASA chief financial officer)
* Trent Franks, former U.S. representative
* Paul Gosar, U.S. representative
* Robert Graham, former chair of the Arizona Republican Party
* Christine Jones, former GoDaddy executive, candidate for governor in 2014 and candidate for AZ-05 in 2016
* Bill Montgomery, Maricopa County Attorney
* Ben Quayle, former U.S. representative
* Matt Salmon, former U.S. representative and nominee for governor in 2002
* David Schweikert, U.S. representative from Arizona's 6th congressional district
* John Shadegg, former U.S. representative

### Endorsements

Federal officials
* Mike Pence, vice president of the United States
United States Senators
* Jon Kyl, twice U.S. Senator (R-AZ) and former Senate minority whip
* Mitch McConnell, U.S. Senator (R-KY) and Senate majority leader
* David Perdue, U.S. Senator (R-GA)
U.S. Representatives
* Newt Gingrich, former House speaker
State officials
* Betsey Bayless, former secretary of state of Arizona
* Jan Brewer, former governor of Arizona
* Jay Heiler, treasurer of the Arizona Board of Regents
Mayors
* Jim Lane (Scottsdale)
* Georgia Lord (Goodyear)
Individuals
* Suzanne Klapp, Scottsdale city councilwoman
Organizations
* Maggie's List
* National Border Patrol Council
* RightNOW Women
* Students For Trump
* Value in Electing Women (VIEW) PAC
* Winning for Women
U.S. Senators
* Rand Paul, U.S. senator (R-KY)
U.S. representatives
* Paul Gosar, U.S. representative (R-AZ)
* Steve King, U.S. representative (R-IA)
* Dana Rohrabacher, U.S. representative (R-CA)
Local officials
* Sylvia Allen, state senator
* Nancy Barto, state senator
* Sonny Borrelli, state senator
* David Farnsworth, state senator
* Mark Finchem, state representative
* Travis Grantham, state representative
* Gail Griffin, state senator
* Al Melvin, former state senator
* Becky Nutt, state representative
* Russell Pearce, former senate president
* Warren Petersen, state senator
U.S. military personnel
* Jessie Jane Duff, retired gunnery sergeant of the U.S. Marine Corps and activist
Individuals
* Steve Bannon, former White House Chief Strategist, executive chairman of Breitbart News
* Mike Cernovich, alt-right media personality and conspiracy theorist
* Sebastian Gorka, former Deputy Assistant to President Donald Trump
* Sean Hannity, conservative talk radio host and host of Hannity on the Fox News Network
* Laura Ingraham, conservative talk radio host and host of The Ingraham Angle on the Fox News Network
* Tomi Lahren, political commentator
* Austin Petersen, candidate for U.S. Senate in Missouri in 2018 and Libertarian candidate for president in 2016
Organizations
* Citizens For Trump
* Great America PAC
* Gun Owners of America

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Joe Arpaio | Martha McSally | Kelli Ward | Other | Undecided |
| Data Orbital | August 21–22, 2018 | 600 | ± 4.0% | 18% | 48% | 22% | 1% | 8% |
| OH Predictive Insights | August 14–15, 2018 | 578 | ± 4.1% | 13% | 47% | 27% | – | 12% |
| OH Predictive Insights | July 23–25, 2018 | 576 | ± 4.1% | 15% | 35% | 27% | – | 23% |
| Gravis Marketing | June 27 – July 2, 2018 | 501 | ± 4.4% | 24% | 36% | 27% | – | 14% |
| Emerson College | June 21–22, 2018 | 305 | ± 5.9% | 18% | 32% | 19% | 7% | 23% |
| Data Orbital | June 19–21, 2018 | 550 | ± 4.2% | 17% | 38% | 23% | 2% | 21% |
| Marist College | June 17–21, 2018 | 371 | ± 6.7% | 21% | 30% | 28% | <1% | 21% |
| OH Predictive Insights | June 11–12, 2018 | 600 | ± 4.0% | 14% | 39% | 25% | – | 22% |
| Remington (R) | May 23–24, 2018 | 2,011 | ± 2.3% | 25% | 42% | 23% | – | 10% |
| Magellan Strategies (R) | April 11–12 and 15, 2018 | 755 | ± 3.6% | 26% | 36% | 25% | 6% | 7% |
| OH Predictive Insights | April 10–11, 2018 | 302 | ± 5.6% | 22% | 27% | 36% | – | 15% |
| Data Orbital | January 11–15, 2018 | 500 | ± 4.4% | 22% | 31% | 19% | – | 27% |
| OH Predictive Insights | January 9, 2018 | 504 | ± 4.4% | 29% | 31% | 25% | – | 15% |
| WPA Intelligence (R) | November 15–16, 2017 | 500 | ± 4.4% | – | 38% | 36% | – | 26% |
| OH Predictive Insights | November 9, 2017 | 323 | ± 5.5% | – | 34% | 42% | – | 24% |
| Revily (R) | October 28–31, 2017 | 380 | ± 3.0% | – | 21% | 32% | 15% | 34% |
with Jay Heiler
| Poll source | Date(s) administered | Sample size | Margin of error | Jay Heiler | Martha McSally | Matt Salmon | David Schweikert | John Shadegg | Kelli Ward | Undecided |
| Data Orbital | October 26–28, 2017 | 500 | ± 4.4% | 1% | 19% | 10% | 5% | 4% | 26% | 28% |
with Jeff Flake
| Poll source | Date(s) administered | Sample size | Margin of error | Jeff Flake | Jeff DeWit | Nicholas Tutora | Kelli Ward | Other | Undecided |
| GBA Strategies | August 30 – September 7, 2017 | 500 | ± 4.4% | 31% | – | – | 58% | – | 11% |
| JMC Analytics (R) | August 26–27, 2017 | 500 | ± 4.4% | 21% | – | 3% | 47% | – | 29% |
| HighGround Public Affairs | August 18–19, 2017 | 273 | ± 5.9% | 28% | – | – | 43% | 5% | 24% |
| Political Marketing International (R-Ward) | February 7, 2017 | 921 | ± 5.0% | 23% | – | – | 30% | – | 47% |
| Remington Research Group | November 15–16, 2016 | 1,122 | ± 2.9% | 30% | 38% | – | 15% | – | 17% |
| Remington Research Group | November 15–16, 2016 | 1,122 | ± 2.9% | 33% | 42% | – | – | – | 25% |
| Remington Research Group | November 15–16, 2016 | 1,122 | ± 2.9% | 35% | 35% | – | – | – | 30% |

### Results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Martha McSally | 357,626 | 54.57% |
| | Republican | Kelli Ward | 180,926 | 27.61% |
| | Republican | Joe Arpaio | 116,555 | 17.79% |
| | Write-in | Write-in | 191 | 0.03% |
| Total votes | Total votes | Total votes | 655,298 | 100.00% |

## Democratic primary
### Candidates
#### On the ballot

* Deedra Abboud, attorney
* Kyrsten Sinema, U.S. representative

#### Failed to file

* Bob Bishop, pilot
* Matt Jette
* David Ruben, physician
* Chris Russell, attorney
* Richard Sherzan, retired administrative law judge, former Iowa state representative and candidate for the U.S. Senate in 2016

#### Withdrew

* Jim Moss, businessman, activist and former teacher

#### Declined

* Randall Friese, state representative
* Mark Kelly, astronaut, scientist, U.S. Navy captain and husband of former U.S. representative Gabby Giffords (later elected to Arizona's Class 3 Senate seat in 2020)
* Ann Kirkpatrick, former U.S. representative and nominee for the U.S. Senate in 2016 (running for AZ-2)
* Greg Stanton, Mayor of Phoenix (running for AZ-9)

### Endorsements

Organizations
* Alliance4Action
* Justice Democrats
* The People for Bernie Sanders
* Progressive Democrats of America
* Vote Pro Choice
Federal officials
* Joe Biden, 47th Vice President of the United States and former U.S. Senator (D-DE)
U.S. senators
* Cory Booker, U.S. senator (D-NJ)
* Catherine Cortez Masto, U.S. senator (D-NV)
* Dennis DeConcini, former U.S. senator (D-AZ)
* Tammy Duckworth, U.S. senator (D-IL)
* Dick Durbin, U.S. senator (D-IL) and Senate Minority Whip
* Kirsten Gillibrand, U.S. senator (D-NY)
* Kamala Harris, U.S. senator (D-CA)
* Mazie Hirono, U.S. senator (D-HI)
* Amy Klobuchar, U.S. senator (D-MN)
* Patrick Leahy, U.S. senator (D-VT)
* Jeff Merkley, U.S. senator (D-OR)
* Chris Murphy, U.S. Senator (D-CT)
* Patty Murray, U.S. senator (D-WA)
* Gary Peters, U.S. Senator (D-MI)
* Chuck Schumer, U.S. senator (D-NY) and Senate Minority Leader
* Ron Wyden, U.S. senator (D-OR)
U.S. representatives
* Ron Barber, former U.S. representative (D-AZ)
* Ruben Gallego, U.S. representative (D-AZ)
* Joe Kennedy III, U.S. representative (D-MA)
* Harry Mitchell, former U.S. representative (D-AZ)
* Tom O'Halleran, U.S. representative (D-AZ)
State and local politicians
* Lela Alston, state representative
* Kelli Butler, state representative
* Andrea Dalessandro, state senator
* Coral Evans, Mayor of Flagstaff
* Randy Friese, state representative and assistant house minority leader
* Francisco Heredia, Mesa city councilmember
* Daniel Hernández Jr., state representative
* Katie Hobbs, state senator and Senate minority leader
* Robert Meza, state senator
* Mark Mitchell, mayor of Tempe
* Joel Navarro, Tempe city councilmember
* Lynne Pancrazi, Yuma County supervisor
* Laura Pastor, Phoenix City Councilmember
* Rebecca Rios, state representative and house minority leader
* Regina Romero, Tucson councilmember
* Jonathan Rothschild, mayor of Tucson
* Anna Tovar, mayor of Tolleson
* Daniel Valenzuela, Phoenix City Councilmember
Individuals
* Jon Favreau, co-host of progressive political podcast Pod Save America and former chief White House speechwriter for President Barack Obama
* Jason Kander, former Missouri Secretary of State, nominee for U.S Senate in Missouri in 2016, host of podcast Majority 54 and founder of Let America Vote
* Jenny Wilson, Salt Lake County Councilwoman; candidate for U.S. Senate in Utah (D-UT)
Labor unions
* Arizona Building and Construction Trades Council
* Arizona Education Association
* Arizona State AFL–CIO
* Communications Workers of America
* International Association of Sheet Metal, Air, Rail and Transportation Workers Local 359
* National Education Association
* United Food and Commercial Workers Local 99
* United Mine Workers of America
Organizations
* Chandler Chamber of Commerce
* Democratic Senatorial Campaign Committee
* EMILY's List
* End Citizens United
* Equality PAC
* Gay & Lesbian Victory Fund
* Human Rights Campaign
* League of Conservation Voters Action Fund
* Let America Vote
* LPAC
* Mesa Chamber of Commerce
* National Organization for Women
* Planned Parenthood Action Fund
* Stonewall Democrats of Arizona

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Deedra Abboud | Kyrsten Sinema | Other | Undecided |
| Data Orbital | June 25–27, 2018 | 550 | ± 4.2% | 7% | 63% | 2% | 29% |
| Emerson College | June 21–22, 2018 | 260 | ± 6.2% | 8% | 51% | 12% | 30% |

### Results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Kyrsten Sinema | 404,170 | 79.25% |
| | Democratic | Deedra Abboud | 105,800 | 20.75% |
| Total votes | Total votes | Total votes | 509,970 | 100.00% |

## Libertarian primary
### Candidates
#### Declared

* Adam Kokesh (write-in candidate), anti-war activist and U.S. presidential candidate in 2020

#### Removed

* Doug Marks, veteran and write-in candidate for IL-14 in 2010

## Green primary
### Candidates
#### Declared

* Angela Green (write-in candidate)

#### Removed

* Eve Reyes-Aguirre, activist

#### Results

Green primary results :
| Party | Party | Candidate | Votes | % |
| | Green | Angela Green (write-in) | 389 | 100.00% |
| Total votes | Total votes | Total votes | 389 | 100.00% |

## General election
### Debates

* Complete video of debate, October 15, 2018

### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Tossup | October 26, 2018 |
| Inside Elections | Tilt D (flip) | November 1, 2018 |
| Sabato's Crystal Ball | Lean D (flip) | November 5, 2018 |
| CNN | Tossup | October 30, 2018 |
| RealClearPolitics | Tossup | November 5, 2018 |
| FiveThirtyEight | Lean D (flip) | November 6, 2018 |
| Daily Kos | Tossup | October 26, 2018 |
| Fox News | Tossup | October 30, 2018 |

### Endorsements

U.S. executive branch Officials
* George W. Bush, 43rd president of the United States
* Betsy DeVos, United States secretary of education
* Mike Pence, 48th vice president of the United States
* Condoleezza Rice, former United States secretary of state
* Donald Trump, 45th president of the United States
U.S. Senators
* John Boozman, U.S. Senator (R-AR)
* Susan Collins, U.S. Senator (R-ME)
* Joni Ernst, U.S. Senator (R-IA)
* Lindsey Graham, U.S. Senator (R-SC)
* Jon Kyl, U.S. Senator (R-AZ) and former Senate Minority Whip
* Mitch McConnell, U.S. Senator (R-KY) and Senate Majority Leader
* David Perdue, U.S. Senator (R-GA)
U.S. representatives
* Liz Cheney, U.S. representative (R-WY) and daughter of former vice president Dick Cheney
* Newt Gingrich, former House speaker
Governors
* Jan Brewer, former governor of Arizona
* Doug Ducey, governor of Arizona
* Mitt Romney, former governor of Massachusetts and Republican nominee for president of the United States in 2012
State officials
* Betsey Bayless, former secretary of state of Arizona
* Karen Fann, state senator
* Jay Heiler, treasurer of the Arizona Board of Regents
* Steve Pierce, former state senator
* Tony Rivero, state representative
* Kelli Ward, former state senator
Local-level officials
* Jim Lane, Scottsdale mayor
* Bill Montgomery, Maricopa County attorney
Individuals
* Rudy Giuliani, former mayor of New York City
* Kimberly Guilfoyle, television news personality
* Donald Trump Jr., businessman and son of President Donald Trump
Organizations
* Citizens Against Government Waste
* Maggie's List
* National Border Patrol Council
* National Federation of Independent Business
* RightNOW Women
* Students For Trump
Newspapers
* The Daily Courier
* National Review
Former U.S. executive branch officials
* Joe Biden, 47th vice president of the United States and former U.S. senator (D-DE)
* Barack Obama, 44th president of the United States
U.S. senators
* Cory Booker, U.S. senator (D-NJ)
* Catherine Cortez Masto, U.S. senator (D-NV)
* Dennis DeConcini, former U.S. senator (D-AZ)
* Tammy Duckworth, U.S. senator (D-IL)
* Dick Durbin, U.S. senator (D-IL) and Senate Minority Whip
* Kirsten Gillibrand, U.S. senator (D-NY)
* Kamala Harris, U.S. senator (D-CA)
* Mazie Hirono, U.S. senator (D-HI)
* Amy Klobuchar, U.S. senator (DFL-MN)
* Patrick Leahy, U.S. senator (D-VT)
* Jeff Merkley, U.S. senator (D-OR)
* Chris Murphy, U.S. senator (D-CT)
* Patty Murray, U.S. senator (D-WA)
* Gary Peters, U.S. senator (D-MI)
* Brian Schatz, U.S. senator (D-HI)
* Chuck Schumer, U.S. senator (D-NY) and Senate Minority Leader
* Ron Wyden, U.S. senator (D-OR)
U.S. representatives
* Ron Barber, former U.S. representative (D-AZ)
* Ruben Gallego, U.S. representative (D-AZ)
* Joe Kennedy III, U.S. representative (D-MA)
* Conor Lamb, U.S. representative (D-PA)
* Harry Mitchell, former U.S. representative (D-AZ)
* Tom O'Halleran, U.S. representative (D-AZ)
State and local politicians
* Lela Alston, state representative
* Kelli Butler, state representative
* Andrea Dalessandro, state senator
* Randy Friese, state representative and state Assistant House Minority Leader
* Daniel Hernández Jr., state representative
* Katie Hobbs, state senator and Senate minority leader
* Robert Meza, state senator
* Lynne Pancrazi, Yuma County supervisor
* Rebecca Rios, state representative and House minority leader
* Jonathan Rothschild, mayor of Tucson
* Anna Tovar, mayor of Tolleson
* Grant Woods, former attorney general of Arizona (Republican)
Individuals
* Jon Favreau, co-host of progressive political podcast Pod Save America and former chief White House speechwriter for President Barack Obama
* Angela Green, small business owner, accountant and Green Party nominee for U.S. Senate in 2018
* Jason Kander, former Missouri Secretary of State, nominee for U.S Senate in Missouri in 2016, host of podcast Majority 54 and founder of Let America Vote
* Amy Schumer, actress
* Amy Siskind, activist and writer
* Jenny Wilson, Salt Lake County councilwoman; candidate for U.S. Senate in Utah (D-UT)
Labor unions
* American Federation of Government Employees District 12
* Arizona Building and Construction Trades Council
* Arizona State AFL–CIO
* Communications Workers of America
* International Association of Sheet Metal, Air, Rail and Transportation Workers Local 359
* National Education Association
* Southwest Regional Council of Carpenters
* United Automobile Workers
* United Food and Commercial Workers Local 99
* United Mine Workers of America
Organizations
* Alliance for Retired Americans
* Democratic Senatorial Campaign Committee
* EMILY's List
* End Citizens United
* Equality PAC
* Feminist Majority Political Action Committee
* High School Democrats of Arizona
* Human Rights Campaign
* League of Conservation Voters Action Fund
* Let America Vote
* LGBTQ Victory Fund
* LPAC
* National Committee to Preserve Social Security and Medicare
* National Organization for Women
* Planned Parenthood Action Fund
* Population Connection
* Rachel's Action Network
* Run with Pride
* Stonewall Democrats of Arizona
Newspapers
* The Arizona Republic

### Fundraising

Campaign finance reports as of October 17, 2018 :
| Candidate (party) | Total receipts | Total disbursements | Cash on hand |
| Kyrsten Sinema (D) | $19,287,249 | $20,249,341 | $1,301,542 |
| Martha McSally (R) | $16,211,836 | $13,688,178 | $2,523,657 |
| Source: Federal Election Commission ||||

### Polling

| Poll source | Date(s) administered | Sample size | Margin of error | Martha McSally (R) | Kyrsten Sinema (D) | Angela Green (G) | Other | Undecided |
| The Trafalgar Group (R) | November 4–5, 2018 | 1,217 | ± 2.8% | 47% | 45% | – | 2% | 6% |
| HarrisX | November 3–5, 2018 | 600 | ± 4.0% | 44% | 49% | – | – | – |
| HarrisX | November 2–4, 2018 | 600 | ± 4.0% | 46% | 47% | – | – | – |
| OH Predictive Insights | November 2–3, 2018 | 631 | ± 3.9% | 49% | 48% | 0% | – | 1% |
| Emerson College | November 1–3, 2018 | 758 | ± 3.7% | 48% | 49% | 2% | – | 2% |
| HarrisX | November 1–3, 2018 | 600 | ± 4.0% | 48% | 46% | – | – | – |
| Research Co. | November 1–3, 2018 | 450 | ± 4.6% | 44% | 45% | – | 1% | 10% |
| HarrisX | October 31 – November 2, 2018 | 600 | ± 4.0% | 49% | 44% | – | – | – |
| Gravis Marketing | October 24 – November 2, 2018 | 1,165 | ± 2.9% | 47% | 46% | – | – | 7% |
| HarrisX | October 30 – November 1, 2018 | 600 | ± 4.0% | 48% | 42% | – | – | – |
| The Trafalgar Group (R) | October 30 – November 1, 2018 | 2,166 | ± 2.1% | 47% | 50% | – | 2% | 1% |
| HarrisX | October 29–31, 2018 | 600 | ± 4.0% | 49% | 42% | – | – | – |
| Vox Populi Polling | October 27–30, 2018 | 677 | ± 3.7% | 48% | 52% | – | – | – |
| HarrisX | October 24–30, 2018 | 1,400 | ± 2.6% | 48% | 43% | – | – | – |
| FOX News | October 27–29, 2018 | 643 LV | ± 3.5% | 46% | 46% | – | 3% | 5% |
| FOX News | October 27–29, 2018 | 710 RV | ± 3.5% | 44% | 45% | – | 4% | 6% |
| CNN/SSRS | October 24–29, 2018 | 702 LV | ± 4.4% | 47% | 51% | – | 0% | 1% |
| CNN/SSRS | October 24–29, 2018 | 867 RV | ± 4.0% | 45% | 48% | – | 0% | 3% |
| HighGround Public Affairs | October 26–28, 2018 | 400 | ± 4.9% | 47% | 45% | 4% | – | 5% |
| NBC News/Marist College | October 23–27, 2018 | 506 LV | ± 5.4% | 44% | 47% | 6% | <1% | 3% |
| NBC News/Marist College | October 23–27, 2018 | 506 LV | ± 5.4% | 44% | 50% | – | 2% | 4% |
| NBC News/Marist College | October 23–27, 2018 | 793 RV | ± 4.4% | 43% | 45% | 7% | <1% | 5% |
| NBC News/Marist College | October 23–27, 2018 | 793 RV | ± 4.4% | 43% | 49% | – | 2% | 6% |
| CBS News/YouGov | October 23–26, 2018 | 972 | ± 4.1% | 44% | 47% | – | 3% | 5% |
| Ipsos | October 17–26, 2018 | 799 | ± 4.0% | 48% | 46% | – | 3% | 3% |
| OH Predictive Insights | October 22–23, 2018 | 600 | ± 4.0% | 52% | 45% | 1% | – | 2% |
| NYT Upshot/Siena College | October 15–19, 2018 | 606 | ± 4.2% | 48% | 46% | 1% | – | 6% |
| Data Orbital | October 16–17, 2018 | 600 | ± 4.0% | 41% | 47% | 3% | 1% | 8% |
| Change Research (D) | October 9–10, 2018 | 783 | – | 44% | 44% | – | – | 11% |
| CBS News/YouGov | October 2–5, 2018 | 898 | – | 44% | 47% | – | 3% | 6% |
| OH Predictive Insights | October 1–2, 2018 | 600 | ± 4.0% | 47% | 41% | 4% | – | 8% |
| FOX News | September 29 – October 2, 2018 | 716 LV | ± 3.5% | 45% | 47% | – | 2% | 6% |
| FOX News | September 29 – October 2, 2018 | 806 RV | ± 3.5% | 44% | 45% | – | 2% | 8% |
| Vox Populi Polling | September 29 – October 1, 2018 | 702 | ± 3.5% | 52% | 49% | – | – | – |
| Suffolk University | September 27–30, 2018 | 500 | ± 4.4% | 42% | 45% | 2% | 0% | 11% |
| Latino Decisions | September 10–25, 2018 | 463 LV | – | 41% | 47% | – | – | 11% |
| Latino Decisions | September 10–25, 2018 | 610 RV | – | 37% | 43% | – | – | 17% |
| Emerson College | September 19–21, 2018 | 650 | ± 4.4% | 39% | 45% | – | 4% | 13% |
| NBC News/Marist College | September 16–20, 2018 | 564 LV | ± 4.7% | 43% | 45% | 6% | <1% | 6% |
| NBC News/Marist College | September 16–20, 2018 | 564 LV | ± 4.7% | 45% | 48% | – | <1% | 7% |
| NBC News/Marist College | September 16–20, 2018 | 763 RV | ± 4.2% | 41% | 44% | 6% | <1% | 8% |
| NBC News/Marist College | September 16–20, 2018 | 763 RV | ± 4.2% | 44% | 47% | – | <1% | 9% |
| CNN/SSRS | September 11–15, 2018 | 761 LV | ± 4.3% | 43% | 50% | – | 0% | 3% |
| CNN/SSRS | September 11–15, 2018 | 854 RV | ± 4.1% | 41% | 48% | – | 1% | 6% |
| Ipsos | September 5–14, 2018 | 1,016 | ± 4.0% | 44% | 47% | – | 4% | 5% |
| TargetSmart (D) | September 8–13, 2018 | 800 | ± 4.0% | 46% | 51% | – | 1% | 3% |
| FOX News | September 8–11, 2018 | 710 LV | ± 3.5% | 44% | 47% | – | 2% | 5% |
| FOX News | September 8–11, 2018 | 801 RV | ± 3.5% | 42% | 46% | – | 3% | 7% |
| Gravis Marketing | September 5–7, 2018 | 882 | ± 3.3% | 49% | 48% | – | – | 3% |
| OH Predictive Insights | September 5–6, 2018 | 597 | ± 4.0% | 49% | 46% | – | – | 6% |
| Data Orbital | September 4–6, 2018 | 550 | ± 4.2% | 42% | 46% | – | 2% | 9% |
| OH Predictive Insights | July 23–24, 2018 | 600 | ± 4.0% | 44% | 48% | – | – | 8% |
| Gravis Marketing | June 27 – July 2, 2018 | 925 | ± 3.2% | 39% | 43% | – | – | 19% |
| SurveyMonkey/Axios | June 11 – July 2, 2018 | 1,290 | ± 4.5% | 44% | 48% | – | – | 7% |
| Emerson College | June 21–22, 2018 | 650 | ± 4.0% | 32% | 40% | – | 9% | 20% |
| CBS News/YouGov | June 19–22, 2018 | 869 LV | – | 37% | 45% | – | 7% | 10% |
| CBS News/YouGov | June 19–22, 2018 | 998 RV | ± 3.7% | 34% | 41% | – | 8% | 14% |
| NBC News/Marist College | June 17–21, 2018 | 839 | ± 4.5% | 38% | 49% | – | 2% | 11% |
| SurveyMonkey/Axios | April 2–23, 2018 | 1,667 | ± 4.0% | 42% | 51% | – | – | 7% |
| OH Predictive Insights | April 10–11, 2018 | 600 | ± 4.0% | 42% | 48% | – | – | 10% |
| Public Policy Polling (D) | March 15–16, 2018 | 547 | ± 4.2% | 41% | 46% | – | – | 13% |
| OH Predictive Insights | November 9, 2017 | 600 | ± 4.0% | 45% | 46% | – | – | 9% |
| Revily (R) | October 28–31, 2017 | 850 | ± 3.4% | 29% | 33% | – | – | 37% |
with Kelli Ward
| Poll source | Date(s) administered | Sample size | Margin of error | Kelli Ward (R) | Kyrsten Sinema (D) | Other | Undecided |
| OH Predictive Insights | July 23–24, 2018 | 600 | ± 4.0% | 41% | 51% | – | 8% |
| Gravis Marketing | June 27 – July 2, 2018 | 925 | ± 3.2% | 37% | 46% | – | 17% |
| SurveyMonkey/Axios | June 11 – July 2, 2018 | 1,290 | ± 4.5% | 41% | 52% | – | 7% |
| Emerson College | June 21–22, 2018 | 650 | ± 4.0% | 26% | 43% | 8% | 23% |
| YouGov | June 19–22, 2018 | 867 LV | ± 3.7% | 38% | 46% | 6% | 9% |
| YouGov | June 19–22, 2018 | 996 RV | ± 3.7% | 35% | 43% | 7% | 14% |
| Marist College | June 17–21, 2018 | 839 | ± 4.5% | 38% | 48% | 2% | 12% |
| SurveyMonkey/Axios | April 2–23, 2018 | 1,667 | ± 4.0% | 43% | 51% | – | 6% |
| OH Predictive Insights | April 10–11, 2018 | 600 | ± 4.0% | 40% | 50% | – | 10% |
| OH Predictive Insights | November 9, 2017 | 600 | ± 4.0% | 43% | 46% | – | 11% |
| Revily (R-Ward) | October 28–31, 2017 | 850 | ± 3.4% | 34% | 33% | – | 33% |
| HighGround Public Affairs | October 23–26, 2017 | 500 | ± 4.4% | 27% | 34% | – | 39% |
| HighGround Public Affairs | August 18–19, 2017 | 400 | ± 4.9% | 31% | 32% | – | 38% |
with Joe Arpaio
| Poll source | Date(s) administered | Sample size | Margin of error | Joe Arpaio (R) | Kyrsten Sinema (D) | Other | Undecided |
| OH Predictive Insights | July 23–24, 2018 | 600 | ± 4.0% | 36% | 54% | – | 10% |
| Gravis Marketing | June 27 – July 2, 2018 | 925 | ± 3.2% | 33% | 52% | – | 14% |
| SurveyMonkey/Axios | June 11 – July 2, 2018 | 1,290 | ± 4.5% | 34% | 57% | – | 9% |
| Emerson College | June 21–22, 2018 | 650 | ± 4.0% | 30% | 54% | 8% | 9% |
| YouGov | June 19–22, 2018 | 868 LV | ± 3.7% | 29% | 49% | 13% | 8% |
| YouGov | June 19–22, 2018 | 996 RV | ± 3.7% | 28% | 45% | 13% | 11% |
| Marist College | June 17–21, 2018 | 839 | ± 4.5% | 32% | 57% | 2% | 9% |
| SurveyMonkey/Axios | April 2–23, 2018 | 1,667 | ± 4.0% | 32% | 61% | – | 7% |
| OH Predictive Insights | April 10–11, 2018 | 600 | ± 4.0% | 33% | 59% | – | 8% |
with generic Republican and generic Democrat
| Poll source | Date(s) administered | Sample size | Margin of error | Generic Republican | Generic Democrat | Undecided |
| Morning Consult | June 29 – July 9, 2018 | 1,641 | ± 2.0% | 35% | 42% | 23% |
| Public Policy Polling (D-Protect Our Care) | March 15–16, 2018 | 547 | ± 4.2% | 47% | 45% | 8% |
with Jeff Flake
| Poll source | Date(s) administered | Sample size | Margin of error | Jeff Flake (R) | Kyrsten Sinema (D) | Undecided |
| GBA Strategies | August 30 – September 7, 2017 | 600 | ± 4.0% | 40% | 47% | 13% |
| HighGround Public Affairs | August 18–19, 2017 | 400 | ± 4.9% | 33% | 41% | 27% |
| Public Policy Polling | May 13–15, 2016 | 896 | ± 3.3% | 38% | 36% | 27% |
| Poll source | Date(s) administered | Sample size | Margin of error | Jeff Flake (R) | Generic Democrat | Undecided |
| Public Policy Polling (D-Our Lives on the Line) | July 31 – August 1, 2017 | 704 | ± 2.0% | 31% | 47% | 22% |
with Matt Salmon
| Poll source | Date(s) administered | Sample size | Margin of error | Matt Salmon (R) | Kyrsten Sinema (D) | Undecided |
| Revily (R-Ward) | October 28–31, 2017 | 850 | ± 3.4% | 30% | 32% | 38% |

### Results

The race was too close to call on election day. On November 7, 2018 (one day after the election), KGUN 9 reported that McSally held a narrow lead of 0.9%, with thousands of ballots still uncounted. On November 8, Politico reported that Sinema had taken a 9,610-vote lead. Due to the closeness of the vote count, the Associated Press and other major news outlets did not call the race for Sinema until November 12, 2018, six days after the election. McSally conceded the race to Sinema that day. The results were certified on December 3, 2018.
This was the first Senate election won by a Democrat in Arizona since 1988. Sinema is the first woman to be elected to the U.S. Senate from Arizona.
United States Senate election in Arizona, 2018 :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Kyrsten Sinema | 1,191,100 | 49.96% | +3.76% |
| | Republican | Martha McSally | 1,135,200 | 47.61% | −1.62% |
| | Green | Angela Green | 57,442 | 2.41% | N/A |
| | Write-in | Write-in | 566 | 0.02% | N/A |
| Total votes | Total votes | Total votes | 2,384,308 | 100.00% | N/A |
| | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican |
By county :
| County | Kyrsten Sinema Democratic | Kyrsten Sinema Democratic | Martha McSally Republican | Martha McSally Republican | Angela Green Green | Angela Green Green | Write-in | Write-in | Margin | Margin | Total votes |
| County | # | % | # | % | # | % | # | % | # | % | Total votes |
| Apache | 16,298 | 64.97 | 7,810 | 31.13 | 961 | 3.83 | 18 | 0.07 | 8,488 | 33.83 | 25,087 |
| Cochise | 17,383 | 38.16 | 26,929 | 59.12 | 1,212 | 2.66 | 25 | 0.05 | -9,546 | -20.96 | 45,549 |
| Coconino | 34,240 | 61.94 | 19,249 | 34.82 | 1,757 | 3.18 | 34 | 0.06 | 14,991 | 27.12 | 55,280 |
| Gila | 7,643 | 37.28 | 12,180 | 59.42 | 674 | 3.29 | 2 | 0.01 | -4,537 | -22.13 | 20,499 |
| Graham | 3,368 | 31.76 | 6,870 | 64.77 | 363 | 3.42 | 5 | 0.05 | -3,502 | -33.02 | 10,606 |
| Greenlee | 1,042 | 40.59 | 1,416 | 55.16 | 108 | 4.21 | 1 | 0.04 | -374 | -14.57 | 2,567 |
| La Paz | 1,609 | 31.72 | 3,265 | 64.36 | 199 | 3.92 | 0 | 0.00 | -1,656 | -32.64 | 5,073 |
| Maricopa | 732,761 | 50.96 | 672,505 | 46.77 | 32,371 | 2.25 | 315 | 0.02 | 60,256 | 4.19 | 1,437,952 |
| Mohave | 19,214 | 26.88 | 50,209 | 70.25 | 2,027 | 2.84 | 19 | 0.03 | -30,995 | -43.37 | 71,469 |
| Navajo | 16,624 | 45.37 | 18,767 | 51.22 | 1,238 | 3.38 | 11 | 0.03 | -2,143 | -5.85 | 36,640 |
| Pima | 221,242 | 56.65 | 160,550 | 41.11 | 8,710 | 2.23 | 66 | 0.02 | 60,692 | 15.54 | 390,568 |
| Pinal | 50,395 | 42.93 | 63,782 | 54.33 | 3,183 | 2.71 | 35 | 0.03 | -13,387 | -11.40 | 117,395 |
| Santa Cruz | 9,241 | 68.51 | 3,828 | 28.38 | 418 | 3.10 | 1 | 0.01 | 5,413 | 40.13 | 13,488 |
| Yavapai | 40,160 | 37.06 | 65,308 | 60.26 | 2,870 | 2.65 | 30 | 0.03 | -25,148 | -23.21 | 108,368 |
| Yuma | 19,880 | 45.42 | 22,532 | 51.48 | 1,351 | 3.09 | 4 | 0.01 | -2,652 | -6.06 | 43,767 |
| Totals | 1,191,100 | 49.96 | 1,135,200 | 47.61 | 57,442 | 2.41 | 566 | 0.02 | 55,900 | 2.34 | 2,384,308 |

#### By congressional district

Sinema won 5 of 9 congressional districts.
| District | Sinema | McSally | Representative |
| 1st | 50.64% | 46.47% | Tom O'Halleran |
| 2nd | 52.63% | 45.23% | Ann Kirkpatrick |
| 3rd | 63.9% | 32.93% | Raúl Grijalva |
| 4th | 32.85% | 64.49% | Paul Gosar |
| 5th | 42.35% | 55.54% | Andy Biggs |
| 6th | 47.4% | 50.81% | David Schweikert |
| 7th | 75.43% | 21.19% | Ruben Gallego |
| 8th | 42.88% | 54.89% | Debbie Lesko |
| 9th | 61.37% | 36.41% | Greg Stanton |

## Aftermath

On December 18, 2018, Governor Doug Ducey appointed McSally to fill Arizona's other Senate seat. The seat was left vacant after the resignation of Jon Kyl, who himself had been appointed following the August 25, 2018 death of John McCain. Both Sinema and McSally were sworn in with the 116th United States Congress on January 3, 2019, marking the first time in history that Arizona was represented by two women in the United States Senate and making Arizona the second state to be represented by two women from different parties. Ducey stipulated that Sinema would be sworn in first, making her the senior senator; this way, he said, the decision of Arizona's voters would be respected.
Under Arizona law, McSally's appointment was only valid for the duration of the 116th Congress, and a special election for her seat was held in November 2020 to determine who would finish the remainder of McCain's unexpired term (which expired in 2023). McSally was defeated by Democrat Mark Kelly in that special election.
Sinema would later leave the Democratic Party to become an independent in December 2022, although she would continue to caucus with them in the Senate until the end of her term.

### Voter demographics

Edison Research exit poll :
| Demographic subgroup | Sinema | McSally | No answer | % of voters |
| Gender |||||
| Men | 49 | 49 | 2 | 47 |
| Women | 51 | 47 | 2 | 53 |
| Age |||||
| 18–24 years old | N/A | N/A | N/A | 4 |
| 25–29 years old | N/A | N/A | N/A | 4 |
| 30–39 years old | 57 | 39 | 4 | 17 |
| 40–49 years old | 50 | 48 | 2 | 17 |
| 50–64 years old | 44 | 55 | 1 | 29 |
| 65 and older | 51 | 48 | 1 | 29 |
| Race |||||
| White | 45 | 53 | 2 | 75 |
| Black | N/A | N/A | N/A | 2 |
| Latino | 68 | 30 | 2 | 18 |
| Asian | N/A | N/A | N/A | 1 |
| Other | N/A | N/A | N/A | 3 |
| Race and gender |||||
| White men | 42 | 55 | 3 | 34 |
| White women | 47 | 52 | 1 | 41 |
| Black men | N/A | N/A | N/A | 1 |
| Black women | N/A | N/A | N/A | 1 |
| Latino men | 66 | 32 | 2 | 9 |
| Latina women | 70 | 28 | 2 | 9 |
| Others | N/A | N/A | N/A | 4 |
| Education |||||
| High school or less | 50 | 46 | 4 | 25 |
| Some college education | 45 | 54 | 1 | 28 |
| Associate Degree | 43 | 53 | 4 | 10 |
| Bachelor's Degree | 52 | 47 | 3 | 23 |
| Advanced degree | 62 | 37 | 1 | 14 |
| Education and race |||||
| White college graduates | 55 | 45 | N/A | 27 |
| White no college degree | 39 | 58 | 3 | 48 |
| Non-white college graduates | 72 | 27 | 1 | 9 |
| Non-white no college degree | 65 | 33 | 2 | 16 |
| Whites by education and gender |||||
| White women with college degrees | 56 | 44 | N/A | 15 |
| White women without college degrees | 42 | 56 | 2 | 26 |
| White men with college degrees | 53 | 47 | N/A | 12 |
| White men without college degrees | 35 | 61 | 4 | 22 |
| Non-whites | 68 | 31 | 1 | 25 |
| Military service |||||
| Veteran | 38 | 59 | 3 | 14 |
| Non-veteran | 54 | 45 | 1 | 86 |
| Income |||||
| Under $30,000 | 62 | 34 | 4 | 15 |
| $30,000-$49,999 | 63 | 36 | 1 | 18 |
| $50,000-$99,999 | 48 | 49 | 3 | 33 |
| $100,000-$199,999 | 41 | 58 | 1 | 24 |
| Over $200,000 | 44 | 56 | N/A | 9 |
| Party ID |||||
| Democrats | 97 | 3 | N/A | 32 |
| Republicans | 12 | 86 | 2 | 38 |
| Independents | 50 | 47 | 3 | 31 |
| Party by gender |||||
| Democratic men | 94 | 6 | N/A | 14 |
| Democratic women | 99 | 1 | N/A | 17 |
| Republican men | 6 | 91 | 3 | 15 |
| Republican women | 16 | 83 | 1 | 23 |
| Independent men | 50 | 47 | 3 | 18 |
| Independent women | 50 | 47 | 3 | 13 |
| Ideology |||||
| Liberals | 94 | 6 | N/A | 22 |
| Moderates | 63 | 35 | 2 | 38 |
| Conservatives | 14 | 84 | 2 | 40 |
| First-time midterm election voter |||||
| Yes | 53 | 44 | 3 | 15 |
| No | 48 | 50 | 2 | 85 |
| Most important issue facing the country |||||
| Health care | 77 | 20 | 3 | 42 |
| Immigration | 16 | 83 | 1 | 31 |
| Economy | 39 | 60 | 1 | 18 |
| Gun policy | N/A | N/A | N/A | 7 |
| Area type |||||
| Urban | 60 | 39 | 1 | 43 |
| Suburban | 44 | 54 | 2 | 51 |
| Rural | N/A | N/A | N/A | 6 |
| Source: CNN |||||