Since Arizona became a U.S. state in 1912, it has sent congressional delegations to the United States Senate and United States House of Representatives, beginning with the 63rd United States Congress in 1913. Before becoming a state, the Arizona Territory elected a non-voting delegate at-large to Congress from 1864 to 1912. Each state elects two senators to serve for six years, and varying numbers of members of the House, depending on state population, to two-year terms. Arizona has sent nine members to the House in each delegation since the 2010 United States Census. A total of 57 people have served Arizona in the House and 14 have served Arizona in the Senate. The first woman to serve Arizona in the House was Isabella Greenway. Seven women have served Arizona in the House, including Kyrsten Sinema and Martha McSally, who also served Arizona in the Senate, the only women to do so. The current dean, or longest serving member, of the Arizona delegation is Representative Raul Grijalva of the AZ's 7th congressional district, who has served in the House since 2003. Carl Hayden was Arizona's longest-serving senator, and his 56 years as a senator is the sixth-longest tenure in American history.

Current delegation

Arizona's current congressional delegation in the consists of its two senators, one Democrat and one independent, and its nine representatives, six Republicans and three Democrats. The current dean, or longest-serving member, of the Arizona delegation is Democratic Representative Raúl Grijalva of the AZ's 7th congressional district, who has served in the House since 2003. As of 2022, the Cook Partisan Voting Index, a measure of how strongly partisan a state is, ranked Arizona's 1st, 5th, 8th, and 9th districts as leaning Republican, and the 2nd, 3rd, 4th, 6th, and 7th districts as leaning Democratic. As a state, Arizona is ranked as leaning Republican, with a score of R+2.

United States Senate

Since it became a state in 1912, 14 people have served as a U.S. senator from Arizona. Of those, Martha McSally and Kyrsten Sinema have been the only women. Sinema is also the first openly bisexual member of Congress. Both senators Barry Goldwater and John McCain have been nominated as the Republican candidate for president, in 1964 and 2008 respectively. Sometimes considered a swing state, elections in Arizona are considered critical for party control of the Senate. Senators are elected every six years depending on their class, with each senator serving a six-year term, and elections for senators occurring every two years, rotating through each class such that in each election, around one-third of the seats in the Senate are up for election. Arizona's senators are elected in classes I and III. Currently, Arizona is represented in the Senate by Kyrsten Sinema and Mark Kelly.

United States House of Representatives

Arizona has had numerous notable representatives in Congress, including Stewart Udall, who resigned to serve as the Secretary of the Interior in the Kennedy administration, his brother, Mo Udall, who came in second in the 1976 Democratic Party presidential primaries, and John Jacob Rhodes, who served as House Minority Leader for the Republican Party during the Watergate scandal. Each district uses a popular vote to elect a member of Arizona's delegation in the House of Representatives. Districts are redrawn every ten years, after data from the US Census is collected. From 1863 to 1912, Arizona sent a non-voting delegate to the House of Representatives; when it became a state in 1912, it had one seat in the House. Since then, its representation in the House has grown along with its population. Since 2013, Arizona has had nine congressional districts drawn according to the results of the 2010 United States Census.

1863–1912: 1 non-voting delegate

Starting on December 5, 1864, Arizona Territory sent a non-voting delegate to the House.

1912–1943: 1 seat

Following statehood on February 14, 1912, Arizona had one seat in the House.

1943–1963: 2 seats

Following the 1940 census, Arizona was apportioned two seats. For six years, the seats were elected statewide on a general ticket. In 1949, districts were used.

1963–1973: 3 seats

Following the 1960 census, Arizona was apportioned three seats.

1973–1983: 4 seats

Following the 1970 census, Arizona was apportioned four seats.

1983–1993: 5 seats

Following the 1980 census, Arizona was apportioned five seats.

1993–2003: 6 seats

Following the 1990 census, Arizona was apportioned six seats.

2003–2013: 8 seats

Following the 2000 census, Arizona was apportioned eight seats.

2013–present: 9 seats

Since the 2010 census, Arizona has been apportioned nine seats.