# 2020 United States Senate special election in Arizona

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vte :
The 2020 United States Senate special election in Arizona was held on November 3, 2020, following the death in office of incumbent Republican U.S. Senator John McCain on August 25, 2018. Governor Doug Ducey was required by Arizona law to appoint a Republican to fill the vacant seat until a special election winner could be sworn in. On September 5, 2018, Ducey appointed former U.S. Senator Jon Kyl to fill McCain's seat. However, Kyl announced he would resign on December 31, 2018.
On December 18, 2018, Ducey announced that outgoing U.S. Representative Martha McSally would be appointed to fill the seat following Kyl's resignation. McSally was sworn in as the state's junior U.S. Senator on January 3, 2019, less than two months after she was defeated by Democrat Kyrsten Sinema for Arizona's Class 1 U.S. Senate seat. McSally ran to complete the term, defeating skincare executive Daniel McCarthy in the Republican primary. She faced former astronaut Mark Kelly, who ran uncontested in the Democratic primary. Primary elections took place on August 4, 2020.
Once a reliably Republican state, Arizona trended more purple in the late 2010s. Kelly significantly outraised McSally and led by about 5% in the average poll leading up to Election Day.
Kelly defeated McSally by a margin of 2.4% on election night, thereby flipping the seat Democratic. As a result, he outperformed Joe Biden in the concurrent presidential election, who defeated President Donald Trump by a margin of 0.3% in the state, but underperformed his polling average. Kelly became the first Democrat to win the Class 3 Senate seat since Carl Hayden won his last term in 1962. This also marked the first time since the 82nd Congress preceding the 1952 election that Democrats held both Senate seats in Arizona.
Kelly was sworn in on December 2, 2020.

## Interim appointments
### Appointees

* Jon Kyl, former U.S. senator, former U.S. Representative for Arizona's 4th congressional district and former Senate Minority Whip, resigned December 31, 2018
* Martha McSally, former U.S. representative for Arizona's 2nd congressional district, 2018 Republican nominee for U.S. Senate, assumed office January 3, 2019

### Potential candidates not appointed

* Kirk Adams, incumbent chief of staff to incumbent governor of Arizona Doug Ducey and former speaker of the Arizona House of Representatives
* Barbara Barrett, Secretary of the Air Force and former United States Ambassador to Finland
* Jan Brewer, former governor of Arizona and former secretary of state of Arizona
* Paul Gosar, incumbent U.S. representative for Arizona's 4th congressional district
* Eileen Klein, former treasurer of Arizona and former chief of staff to former governor of Arizona Jan Brewer
* Cindy McCain, widow of former U.S. senator John McCain
* Meghan McCain, daughter of former U.S. senator John McCain
* Mick McGuire, incumbent adjutant general of the Arizona National Guard
* Karrin Taylor Robson, businesswoman and incumbent member of the Arizona Board of Regents
* Matt Salmon, former U.S. representative, 2002 gubernatorial nominee and former chairperson of the Arizona Republican Party
* David Schweikert, incumbent U.S. representative for Arizona's 6th congressional district
* John Shadegg, former U.S. representative for Arizona's 3rd congressional district
* Kelli Ward, former candidate for U.S. Senate in 2016 and 2018
* Grant Woods, former Republican Arizona Attorney General and former congressional chief of staff to former U.S. senator John McCain

## Republican primary

Incumbent McSally faced one challenger: Daniel McCarthy, a skincare company executive. McCarthy's independent wealth was expected to set up a bruising and expensive primary campaign; however, McSally won the primary in a landslide.

### Candidates
#### Nominee

* Martha McSally, incumbent U.S. senator and former U.S. Representative for Arizona's 2nd congressional district

#### Eliminated in primary

* Sean Lyons (as a write-in candidate)
* Daniel McCarthy, skincare company executive

#### Withdrawn

* Craig Brittain, former revenge porn site operator
* PT Burton
* Mark Cavener
* Floyd Getchell
* Ann Griffin, former teacher
* Josue Larose, 2016 Republican presidential candidate and 2012 Republican candidate for Louisiana's 2nd congressional district

#### Declined

* Kirk Adams, incumbent chief of staff to incumbent governor of Arizona Doug Ducey and former Speaker of the Arizona House of Representatives
* Joe Arpaio, former Sheriff of Maricopa County and candidate for U.S. Senate in 2018 (running for Maricopa County Sheriff)
* Doug Ducey, governor of Arizona
* Paul Gosar, U.S. representative for Arizona's 4th congressional district (ran for re-election)
* Jon Kyl, former U.S. senator, former U.S. Representative for Arizona's 4th congressional district and former Senate Minority Whip
* Blake Masters, president of the Thiel Foundation
* Curt Schilling, former Major League Baseball player and Blaze Media commentator
* Fife Symington, former governor of Arizona

### Endorsements

U.S. presidents
* George W. Bush, 43rd president of the United States
* Donald Trump, 45th president of the United States
State officials
* Doug Ducey, Governor of Arizona (2015–2023)
Individuals
* Buzz Aldrin, U.S. astronaut
Organizations
* Campaign for Working Families
* Huck PAC
* Maggie's List
* Republican Jewish Coalition
* Susan B. Anthony List

### Primary results

Republican primary results :
| Party | Party | Candidate | Votes | % |
| | Republican | Martha McSally (incumbent) | 551,119 | 75.2% |
| | Republican | Daniel McCarthy | 181,551 | 24.8% |
| | Republican | Sean Lyons (write-in) | 210 | nil |
| Total votes | Total votes | Total votes | 732,880 | 100.0% |

## Democratic primary
### Candidates
#### Nominee

* Mark Kelly, retired astronaut, engineer, retired U.S. Navy captain, husband of former U.S. Representative Gabby Giffords

#### Eliminated in primary

* Bo "Heir Archy" Garcia (as a write-in candidate)

#### Withdrew

* Mohammad Arif, businessman and perennial candidate (write-in) (switched to Democratic general election write-in candidacy)
* Sheila Bilyeu, Democratic candidate for the 2020 United States Senate election in Oklahoma
* Juan Angel Vasquez

#### Declined

* Ruben Gallego, incumbent U.S. representative for Arizona's 7th congressional district (running for re-election) (endorsed Mark Kelly)
* Katie Hobbs, Secretary of State of Arizona
* Grant Woods, former Republican Arizona Attorney General and former congressional chief of staff to former U.S. senator John McCain

### Endorsements

U.S. presidents
* Barack Obama, 44th president of the United States
U.S. senators
* Kamala Harris, U.S. senator from California
* Amy Klobuchar, U.S. senator from Minnesota
* Kyrsten Sinema, U.S. senator from Arizona
U.S. representatives
* Ruben Gallego, U.S. representative (AZ-07)
Organizations
* 314 Action
* Brady Campaign
* Coalition to Stop Gun Violence
* Council for a Livable World
* Democratic Senatorial Campaign Committee
* End Citizens United
* Everytown for Gun Safety
* Feminist Majority PAC
* High School Democrats of America
* Human Rights Campaign
* Joint Action Committee for Political Affairs
* League of Conservation Voters
* NARAL Pro-Choice America
* National Organization for Women
* Planned Parenthood Action Fund
* Sierra Club
* Stonewall Democrats of Arizona
* Students for Gun Legislation
* VoteVets

### Primary results

Democratic primary results :
| Party | Party | Candidate | Votes | % |
| | Democratic | Mark Kelly | 665,620 | 99.9% |
| | Democratic | Bo Garcia (write-in) | 451 | 0.1% |
| Total votes | Total votes | Total votes | 666,071 | 100.0% |

## Libertarian primary

Neither one of the write-in candidates received enough votes to secure the Libertarian nomination in the general election.

### Write-in candidates
#### Eliminated in primary

* Barry Hess, write-in Libertarian candidate in the 2018 United States Senate election in Arizona and Libertarian nominee in the 2014 Arizona gubernatorial election
* Alan White

### Primary results

Libertarian primary results :
| Party | Party | Candidate | Votes | % |
| | Libertarian | Barry Hess (write-in) | 329 | 76.5% |
| | Libertarian | Alan White (write-in) | 101 | 23.5% |
| Total votes | Total votes | Total votes | 430 | 100.0% |

## Other candidates
### General election write-in candidates
#### Declared

Republican
* Edward Davida
* John Schiess
* Debbie Simmons
* Patrick "Pat" Thomas
Democratic
* Mohammed "Mike Obama" Arif
* Adam Chilton
* Perry Kapadia
* Buzz Stewart
Other
* Christopher Beckett, veteran (Independent)
* William "Will" Decker (Independent)
* Matthew "Doc" Dorchester (Libertarian)
* Nicholas N. Glenn, Navy veteran and aerospace engineer (Independent Republican)
* Mathew Haupt (Independent)
* Benjamin Rodriguez (Independent)
* Joshua Rodriguez (Unity)
* Frank Saenz (Independent)
* Jim Stevens (Independent)

#### Withdrawn

* Robert Kay (Independent)

## General election
### Debates

* Complete video of debate, October 6, 2020

### Predictions

| Source | Ranking | As of |
| The Cook Political Report | Lean D (flip) | October 29, 2020 |
| Inside Elections | Tilt D (flip) | October 28, 2020 |
| Sabato's Crystal Ball | Lean D (flip) | November 2, 2020 |
| Daily Kos | Lean D (flip) | October 30, 2020 |
| Politico | Lean D (flip) | November 2, 2020 |
| RCP | Tossup | October 23, 2020 |
| DDHQ | Likely D (flip) | November 3, 2020 |
| 538 | Likely D (flip) | November 2, 2020 |
| Economist | Lean D (flip) | November 2, 2020 |

### Post-primary endorsements

Federal officials
* Nikki Haley, former U.S. Ambassador to the UN (2017–2018) and former governor of South Carolina (2011–2017)
Newspapers
* Casa Grande Dispatch
Federal officials
* Seth Moulton, U.S. representative from MA-06
Organizations
* Center for Biological Diversity
* Climate Hawks Vote
* Equality Arizona
* J Street
* MoveOn
* National Education Association
* Natural Resources Defense Council Action Fund
Unions
* United Auto Workers
Newspapers
* Arizona Daily Star
Individuals
* Kerry Washington, actress

### Polling
#### Aggregate polls

Mark Kelly vs. Martha McSally :
| Source of poll aggregation | Dates administered | Dates updated | Mark Kelly | Martha McSally | Margin |
| 270 to Win | November 2, 2020 | November 3, 2020 | 49.8% | 44.8% | Kelly +5.0 |
| Real Clear Politics | November 1, 2020 | November 3, 2020 | 50.5% | 44.8% | Kelly +5.7 |
| Average | Average | Average | 50.2% | 44.8% | Kelly +5.4 |
Polling :
| Poll source | Date(s) administered | Sample size | Margin of error | Martha McSally (R) | Mark Kelly (D) | Other / Undecided |
| Ipsos/Reuters | October 27 – November 2, 2020 | 610 (LV) | ± 4.5% | 44% | 53% | 4% |
| Change Research/CNBC | October 29 – November 1, 2020 | 409 (LV) | ± 4.9% | 47% | 51% | 2% |
| NBC News/Marist | October 29 – November 1, 2020 | 717 (LV) | ± 4.5% | 46% | 52% | 2% |
| Swayable | October 27 – November 1, 2020 | 333 (LV) | ± 7.2% | 45% | 55% | – |
| Data for Progress | October 27 – November 1, 2020 | 1,195 (LV) | ± 2.8% | 46% | 54% | 0% |
| Emerson College | October 29–31, 2020 | 732 (LV) | ± 3.6% | 48% | 50% | 2% |
| Morning Consult | October 22–31, 2020 | 1,059 (LV) | ± 3% | 44% | 48% | – |
| Data Orbital | October 28–30, 2020 | 550 (LV) | ± 4.2% | 46% | 47% | 7% |
| Siena College/NYT Upshot | October 26–30, 2020 | 1,253 (LV) | ± 3% | 43% | 50% | 6% |
| Grand Canyon Battleground Poll | October 25–30, 2020 | 910 (LV) | ± 3.1% | 43% | 46% | 11% |
| CNN/SSRS | October 23–30, 2020 | 892 (LV) | ± 4.0% | 45% | 51% | 5% |
| Pulse Opinion Research/Rasmussen Reports | October 27–29, 2020 | 800 (LV) | ± 3.5% | 43% | 48% | 9% |
| Gravis Marketing | October 26–28, 2020 | 704 (LV) | ± 3.7% | 45% | 50% | 6% |
| Ipsos/Reutuers | October 21–27, 2020 | 714 (LV) | ± 4.2% | 44% | 51% | 5% |
| Swayable | October 23–26, 2020 | 286 (LV) | ± 7.4% | 44% | 56% | – |
| Justice Collaborative Project (D) | October 22–25, 2020 | 874 (LV) | ± 3.1% | 40% | 50% | 10% |
| OH Predictive Insights | October 22–25, 2020 | 716 (LV) | ± 3.7% | 45% | 50% | 4% |
| Univision/University of Houston/Latino Decisions/Latino Decisions/North Star Opinion Research | October 17–25, 2020 | 725 (RV) | ± 3.6% | 39% | 51% | 10% |
| Patinkin Research Strategies (D) | October 21–24, 2020 | 729 (LV) | ± 3.6% | 46% | 53% | 2% |
| Y2 Analytics | October 15–24, 2020 | 700 (LV) | ± 3.7% | 47% | 51% | – |
| Susquehanna Polling & Research Inc. (R) | October 19–22, 2020 | 500 (LV) | ± 4.4% | 50% | 47% | 4% |
| Ipsos/Reuters | October 14–21, 2020 | 658 (LV) | ± 4.4% | 43% | 51% | 5% |
| Morning Consult | October 11–20, 2020 | 1,066 (LV) | ± 3% | 44% | 48% | – |
| Pulse Opinion Research/Rasmussen Reports | October 18–19, 2020 | 800 (LV) | ± 3.5% | 44% | 46% | 10% |
| Change Research/CNBC | October 16–19, 2020 | 232 (LV) | – | 43% | 54% | – |
| RMG Research | October 14–19, 2020 | 800 (LV) | ± 3.5% | 39% | 49% | 15% |
| RMG Research | October 14–19, 2020 | 800 (LV) | ± 3.5% | 37% | 49% | 15% |
| RMG Research | October 14–19, 2020 | 800 (LV) | ± 3.5% | 40% | 44% | 15% |
| Data Orbital | October 16–18, 2020 | 550 (LV) | ± 4.2% | 42% | 48% | 10% |
| YouGov/CBS | October 13–16, 2020 | 1,074 (LV) | ± 4.1% | 41% | 52% | 7% |
| Ipsos/Reuters | October 7–14, 2020 | 667 (LV) | ± 4.3% | 41% | 52% | 8% |
| Monmouth University | October 9–13, 2020 | 502 (RV) | ± 4.4% | 42% | 52% | 5% |
| Monmouth University | October 9–13, 2020 | 502 (LV) | ± 4.4% | 42% | 52% | – |
| Monmouth University | October 9–13, 2020 | 502 (LV) | ± 4.4% | 45% | 51% | – |
| Morning Consult | October 2–11, 2020 | 1,144 (LV) | ± 2.9% | 41% | 49% | – |
| Trafalgar Group | October 6–9, 2020 | 1,045 (LV) | ± 3.0% | 45% | 47% | 7% |
| OH Predictive Insights | October 4–8, 2020 | 608 (LV) | ± 4.0% | 45% | 50% | 6% |
| Ipsos/Reuters | September 29 – October 7, 2020 | 663 (LV) | ± 4.3% | 41% | 51% | 8% |
| Latino Decisions (D) | September 28 – October 6, 2020 | 600 (LV) | ± 4% | 42% | 47% | 7% |
| Basswood Research (R) | October 3–5, 2020 | 800 (LV) | ± 3.5% | 49% | 47% | 4% |
| Data Orbital | October 3–5, 2020 | 550 (LV) | ± 4.2% | 44% | 49% | 7% |
| HighGround Inc. | September 28 – October 5, 2020 | 400 (LV) | ± 4.9% | 44% | 50% | 7% |
| Change Research/CNBC | October 2–4, 2020 | 296 (LV) | – | 43% | 51% | 6% |
| Siena College/NYT Upshot | October 1–3, 2020 | 655 (LV) | ± 4.2% | 39% | 50% | 11% |
| Patinkin Research Strategies/Arizona Research Consortium (D) | October 1–3, 2020 | 604 (LV) | ± 3.8% | 45% | 50% | 5% |
| Targoz Market Research | September 23 – October 2, 2020 | 1,045 (LV) | ± nil | 41% | 51% | 8% |
| Morning Consult | September 22 – October 1, 2020 | 1,048 (LV) | ± 3% | 38% | 51% | 10% |
| Suffolk University | September 26–30, 2020 | 500 (LV) | ± 4.4% | 40% | 49% | 11% |
| Susquehanna Polling & Research Inc. (R) | September 25–28, 2020 | 500 (LV) | ± 4.3% | 45% | 48% | – |
| Data for Progress (D) | September 23–28, 2020 | 808 (LV) | ± 3.4% | 42% | 51% | 7% |
| Morning Consult | September 19–28, 2020 | ~1,000 (LV) | ± 3% | 36% | 53% | 10% |
| Data For Progress | September 15–22, 2020 | 481 (LV) | ± 4.4% | 38% | 47% | 15% |
| Change Research/CNBC | September 18–20, 2020 | 262 (LV) | – | 43% | 51% | 6% |
| ABC News/Washington Post | September 15–20, 2020 | 579 (LV) | ± 4.5% | 48% | 49% | 3% |
| Morning Consult | September 11–20, 2020 | 907 (LV) | ± 3% | 40% | 49% | – |
| Hart Research Associates (D) | September 17–19, 2020 | 400 (LV) | ± 4.9% | 43% | 55% | – |
| Ipsos/Reuters | September 11–17, 2020 | 565 (LV) | ± 4.7% | 41% | 50% | 8% |
| Morning Consult | September 8–17, 2020 | 900 (LV) | ± (2% – 4%) | 41% | 48% | – |
| Fabrizio, Lee & Associates (R) | September 14–16, 2020 | 800 (LV) | ± 3.5% | 46% | 48% | 6% |
| Redfield & Wilton Strategies | September 12–16, 2020 | 855 (LV) | ± 3.4% | 35% | 53% | 13% |
| Monmouth University | September 11–15, 2020 | 420 (RV) | ± 4.8% | 44% | 50% | 5% |
| Monmouth University | September 11–15, 2020 | 420 (LV) | ± 4.8% | 46% | 50% | 4% |
| Monmouth University | September 11–15, 2020 | 420 (LV) | ± 4.8% | 48% | 49% | 4% |
| Siena College/NYT Upshot | September 10–15, 2020 | 653 (LV) | ± 4.1% | 42% | 50% | 8% |
| Morning Consult | September 5–14, 2020 | ~1,000 (LV) | ± 3% | 38% | 50% | 13% |
| Patinkin Research Strategies/Arizona Research Consortium (D) | September 10–13, 2020 | 679 (LV) | ± 3.8% | 45% | 50% | 5% |
| Kaiser Family Foundation/Cook Political Report | August 29 – September 13, 2020 | 1,298 (RV) | ± 3.0% | 36% | 44% | 20% |
| Gravis Marketing | September 10–11, 2020 | 684 (LV) | ± 3.8% | 43% | 48% | 9% |
| YouGov/CBS | September 9–11, 2020 | 1,106 (LV) | ± 3.9% | 42% | 49% | 9% |
| OH Predictive Insights | September 8–10, 2020 | 600 (LV) | ± 4% | 42% | 52% | 6% |
| Benenson Strategy Group/GS Strategy Group | August 28 – September 8, 2020 | 1,600 (LV) | ± 2.5% | 45% | 48% | 7% |
| Change Research/CNBC | September 4–6, 2020 | 470 (LV) | ± 4.6% | 45% | 51% | 4% |
| Redfield & Wilton Strategies | August 30 – September 4, 2020 | 830 (LV) | ± 3.4% | 38% | 53% | 8% |
| Morning Consult | August 26 – September 4, 2020 | ~1,000 (LV) | ± 3% | 39% | 50% | 11% |
| FOX News | August 29 – September 1, 2020 | 772 (LV) | ± 3.5% | 39% | 56% | 5% |
| FOX News | August 29 – September 1, 2020 | 853 (RV) | ± 3.0% | 38% | 55% | 6% |
| Basswood Research (R) | August 29–31, 2020 | 800 (LV) | ± 3.5% | 48% | 48% | 4% |
| Morning Consult | August 16–25, 2020 | ~1,000 (LV) | ± 3% | 35% | 53% | 13% |
| Redfield and Wilton Strategies | August 16–18, 2020 | 856 (LV) | ± 3.4% | 34% | 53% | 12% |
| Morning Consult | August 6–15, 2020 | ~1,000 (LV) | ± 3% | 43% | 46% | 11% |
| Emerson College | August 8–10, 2020 | 661 (LV) | ± 3.8% | 41% | 52% | 7% |
| Change Research/CNBC | August 7–9, 2020 | 428 (LV) | ± 4.6% | 43% | 49% | 8% |
| Morning Consult | July 27 – August 5, 2020 | ~1,000 (LV) | ± 3% | 38% | 49% | 13% |
| OH Predictive Insights | August 3–4, 2020 | 603 (LV) | ± 4.0% | 43% | 48% | 9% |
| OnMessage Inc. (R) | August 2–4, 2020 | 400 (LV) | ± 4.9% | 48% | 48% | 4% |
| Data for Progress | July 24 – August 2, 2020 | 1,215 (LV) | ± 3.2% | 40% | 50% | 10% |
| Change Research/CNBC | July 24–26, 2020 | 365 (LV) | ± 4.8% | 45% | 47% | 8% |
| Morning Consult | July 17–26, 2020 | 908 (LV) | ± 3.0% | 36% | 52% | 13% |
| CNN/SSRS | July 18–24, 2020 | 873 (RV) | ± 3.8% | 43% | 50% | 7% |
| Redfield & Wilton Strategies | July 19–23, 2020 | 858 (LV) | ± 3.2% | 35% | 53% | 13% |
| Morning Consult | July 14–23, 2020 | ~1,000 (LV) | ± 3% | 39% | 49% | 12% |
| Public Policy Polling | July 21–22, 2020 | 816 (V) | ± 3.2% | 42% | 51% | 7% |
| NBC News/Marist | July 14–22, 2020 | 826 (RV) | ± 4.1% | 41% | 53% | 6% |
| Spry Strategies (R) | July 11–16, 2020 | 700 (LV) | ± 3.7% | 41% | 48% | 11% |
| Change Research/CNBC | July 10–12, 2020 | 345 (LV) | ± 4.6% | 45% | 52% | 3% |
| CBS News/YouGov | July 7–10, 2020 | 1,087 (LV) | ± 3.8% | 42% | 46% | 12% |
| OH Predictive Insights | July 6–7, 2020 | 600 (LV) | ± 4.0% | 43% | 52% | 6% |
| Data Orbital | June 27–29, 2020 | 600 (LV) | ± 4.0% | 43% | 50% | 7% |
| Gravis Marketing (R) | June 27, 2020 | 527 (LV) | ± 4.3% | 46% | 42% | 12% |
| Change Research/CNBC | June 26–28, 2020 | 311 (LV) | ± 5.8% | 44% | 53% | 3% |
| Global Strategy Group (D) | June 19–24, 2020 | 800 (LV) | ± 3.5% | 42% | 49% | 9% |
| Change Research (D) | June 20–23, 2020 | 946 (LV) | ± 3.2% | 42% | 50% | 8% |
| Redfield & Wilton Strategies | June 14–17, 2020 | 865 (LV) | ± 3.3% | 34% | 49% | 17% |
| NYT Upshot/Siena College | June 8–16, 2020 | 650 (RV) | ± 4.3% | 38% | 47% | 16% |
| Civiqs/Daily Kos | June 13–15, 2020 | 1,368 (RV) | ± 2.9% | 42% | 51% | 7% |
| FOX News | May 30 – June 2, 2020 | 1,002 (RV) | ± 3.9% | 37% | 50% | 13% |
| HighGround Public Affairs | May 18–22, 2020 | 400 (LV) | ± 4.9% | 41% | 51% | 8% |
| OH Predictive Insights | May 9–11, 2020 | 600 (LV) | ± 4.0% | 38% | 51% | 10% |
| OH Predictive Insights | April 7–8, 2020 | 600 (LV) | ± 4.0% | 42% | 51% | 8% |
| NBC News/Marist | March 10–15, 2020 | 2,523 (RV) | ± 2.7% | 45% | 48% | 7% |
| Monmouth University | March 11–14, 2020 | 847 (RV) | ± 3.4% | 44% | 50% | 6% |
| Univision/Arizona State University | March 6–11, 2020 | 1,036 (RV) | ± 3.0% | 36% | 48% | 16% |
| OH Predictive Insights | March 3–4, 2020 | 600 (LV) | ± 4.0% | 42% | 49% | 9% |
| Public Policy Polling | March 2–3, 2020 | 666 (V) | ± 3.8% | 42% | 47% | 12% |
| HighGround Public Affairs | February 7–9, 2020 | 400 (LV) | ± 4.9% | 39% | 46% | 15% |
| Fabrizio, Lee & Associates (R) | January 22–24, 2020 | 1,000 (LV) | ± 3.1% | 47% | 45% | 8% |
| Public Policy Polling | January 2–4, 2020 | 760 (V) | ± 3.6% | 42% | 46% | 12% |
| OH Predictive Insights | December 3–4, 2019 | 628 (LV) | ± 3.9% | 44% | 47% | 9% |
| Emerson College | October 25–28, 2019 | 904 (RV) | ± 3.2% | 45% | 46% | 9% |
| Change Research (D) | September 27–28, 2019 | 856 (RV) | ± 3.3% | 45% | 47% | 8% |
| Bendixen & Amandi International | September 9–12, 2019 | 520 (RV) | ± 4.3% | 42% | 42% | 16% |
| OH Predictive Insights | August 13–14, 2019 | 600 (LV) | ± 4.0% | 41% | 46% | 13% |
| Fabrizio Ward/AARP | July 29–31, 2019 | 600 (LV) | ± 4.0% | 45% | 44% | 11% |
| OH Predictive Insights | May 1–2, 2019 | 600 (LV) | ± 4.0% | 45% | 44% | 11% |
| OH Predictive Insights | February 12–13, 2019 | 600 (LV) | ± 4.0% | 46% | 44% | 10% |
with Daniel McCarthy and Mark Kelly
| Poll source | Date(s) administered | Sample size | Margin of error | Daniel McCarthy (R) | Mark Kelly (D) | Other / Undecided |
| Change Research | June 20–23, 2020 | 946 (LV) | ± 3.2% | 44% | 50% | 6% |
with Ruben Gallego
| Poll source | Date(s) administered | Sample size | Margin of error | Martha McSally (R) | Ruben Gallego (D) | Other / Undecided |
| OH Predictive Insights | February 12–13, 2019 | 600 (LV) | ± 4.0% | 49% | 41% | 10% |
on whether McSally deserves to be re-elected
| Poll source | Date(s) administered | Sample size | Margin of error | Yes | No | Other / Undecided |
| Fabrizio Ward/AARP | July 29–31, 2019 | 600 (LV) | ± 4.0% | 39% | 45% | 16% |
| Public Policy Polling | January 24–25, 2019 | 682 (V) | – | 40% | 54% | 6% |
with generic Republican and generic Democrat
| Poll source | Date(s) administered | Sample size | Margin of error | Generic Republican | Generic Democrat | Other / Undecided |
| OH Predictive Insights | October 4–8, 2020 | 608 (LV) | ± 4.0% | 45% | 45% | 10% |
| Targoz Market Research/PollSmart | September 23 – October 2, 2020 | 1,045 (LV) | ± 3.0% | 44% | 42% | 14% |
| Data For Progress | September 15–22, 2020 | 481 (LV) | ± 4.4% | 45% | 42% | 15% |
| Siena College/NYT Upshot | September 10–15, 2020 | 653 (LV) | ± 4.1% | 44% | 50% | 6% |
| Emerson College | August 8–10, 2020 | 661 (LV) | ± 3.8% | 41% | 46% | 13% |
| OnMessage Inc. (R) | August 2–4, 2020 | 400 (LV) | ± 4.9% | 43% | 43% | 14% |
| Climate Nexus | Feb 11–15, 2020 | 539 (RV) | ± 4.3% | 44% | 44% | 12% |
| Fabrizio, Lee & Associates (R) | Jan 22–24, 2020 | 1,000 (LV) | ± 3.1% | 49% | 45% | 6% |
| OH Predictive Insights | December 3–4, 2019 | 628 (LV) | ± 3.9% | 44% | 44% | 11% |
| Fabrizio Ward/AARP | July 29–31, 2019 | 600 (LV) | ± 4.0% | 42% | 43% | 14% |
| OH Predictive Insights | February 12–13, 2019 | 600 (LV) | ± 4.0% | 44% | 39% | 17% |

### Results

2020 United States Senate Special election in Arizona :
| Party | Party | Candidate | Votes | % | ±% |
| | Democratic | Mark Kelly | 1,716,467 | 51.16% | +10.41% |
| | Republican | Martha McSally (incumbent) | 1,637,661 | 48.81% | −4.90% |
| | Write-in | Write-in | 1,169 | 0.03% | -0.03% |
| Total votes | Total votes | Total votes | 3,355,297 | 100.0% | |
| | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican | Democratic gain from Republican |

#### By county

By county :
| County | Mark Kelly Democratic | Mark Kelly Democratic | Martha McSally Republican | Martha McSally Republican | Write-in | Write-in | Margin | Margin | Total votes |
| County | # | % | # | % | # | % | # | % | Total votes |
| Apache | 24,050 | 68.47 | 11,052 | 31.47 | 22 | 0.06 | 12,998 | 37.01 | 35,124 |
| Cochise | 24,843 | 41.35 | 35,214 | 58.61 | 29 | 0.05 | -10,371 | -17.26 | 60,086 |
| Coconino | 45,561 | 62.54 | 27,255 | 37.41 | 29 | 0.04 | 18,306 | 25.13 | 72,845 |
| Gila | 9,648 | 35.02 | 17,889 | 64.94 | 11 | 0.04 | -8,241 | -29.91 | 27,548 |
| Graham | 4,506 | 30.42 | 10,303 | 69.55 | 4 | 0.03 | -5,797 | -39.13 | 14,813 |
| Greenlee | 1,403 | 38.65 | 2,225 | 61.29 | 2 | 0.06 | -822 | -22.66 | 3,630 |
| La Paz | 2,492 | 34.00 | 4,835 | 65.97 | 2 | 0.03 | -2,343 | -31.97 | 7,329 |
| Maricopa | 1,064,396 | 51.94 | 984,203 | 48.03 | 698 | 0.03 | 80,193 | 3.91 | 2,049,297 |
| Mohave | 27,414 | 26.66 | 75,359 | 73.29 | 49 | 0.05 | -47,945 | -46.63 | 102,822 |
| Navajo | 24,396 | 47.49 | 26,952 | 52.47 | 21 | 0.04 | -2,556 | -4.98 | 51,369 |
| Pima | 309,142 | 59.84 | 207,317 | 40.13 | 152 | 0.03 | 101,825 | 19.71 | 516,611 |
| Pinal | 79,114 | 43.18 | 104,048 | 56.78 | 76 | 0.04 | -24,934 | -13.61 | 183,238 |
| Santa Cruz | 13,689 | 70.65 | 5,685 | 29.34 | 2 | 0.01 | 8,004 | 41.31 | 19,376 |
| Yavapai | 51,852 | 36.49 | 90,180 | 63.47 | 57 | 0.04 | -38,328 | -26.97 | 142,089 |
| Yuma | 33,961 | 49.13 | 35,144 | 50.84 | 15 | 0.02 | -1,183 | -1.71 | 69,120 |
| Totals | 1,716,467 | 51.16 | 1,637,661 | 48.81 | 1,189 | 0.03 | 78,826 | 2.35 | 3,355,317 |

#### By congressional district

Kelly won 5 of the 9 congressional districts.
| District | McSally | Kelly | Representative |
| 1st | 48% | 52% | Tom O'Halleran |
| 2nd | 44% | 56% | Ann Kirkpatrick |
| 3rd | 35% | 65% | Raúl Grijalva |
| 4th | 67% | 33% | Paul Gosar |
| 5th | 56% | 44% | Andy Biggs |
| 6th | 52% | 48% | David Schweikert |
| 7th | 24% | 76% | Ruben Gallego |
| 8th | 57% | 43% | Debbie Lesko |
| 9th | 38% | 62% | Greg Stanton |