The 109th United States Congress began on January 3, 2005. There were nine new senators (two Democrats, seven Republicans) and 40 new representatives (16 Democrats, 24 Republicans) at the start of its first session. Additionally, one senator (a Democrat) and six representatives (two Democrats, four Republicans) took office on various dates in order to fill vacancies during the 109th Congress before it ended on January 3, 2007.
| District | Representative | Switched party | Prior background | Birth year | ||
|---|---|---|---|---|---|---|
| Daniel Lungren (R) | No | Former Congressman | 1946 | |||
| Jim Costa (D) | No | Family farmer | 1952 | |||
| John Salazar (D) | Yes | Soldier | 1953 | |||
| Connie Mack IV (R) | No | State Representative | 1967 | |||
| Debbie Wasserman Schultz (D) | No | State Representative State Senator | 1966 | |||
| Cynthia McKinney (D) | No | Former Congresswoman | 1955 | |||
| Tom Price (R) | No | State Senator | 1954 | |||
| Lynn Westmoreland (R) | No | State Representative | 1950 | |||
| John Barrow (D) | Yes | Athens City Council, Athens County Commissioner | 1955 | |||
| Dan Lipinski (D) | No | Political assistant, college professor | 1966 | |||
| Melissa Bean (D) | Yes | Sales executive | 1962 | |||
| Mike Sodrel (R) | Yes | Guardsman, automotive executive | 1945 | |||
| Geoff Davis (R) | Yes | Ranger, manufacturing consultant | 1958 | |||
| Bobby Jindal (R) | No | Consultant | 1971 | |||
| Charlie Melancon (D) | Yes | State Representative, Small business owner | 1947 | |||
| Charles Boustany (R) | Yes | Surgeon | 1956 | |||
| Joe Schwarz (R) | No | Physician | 1937 | |||
| Russ Carnahan (D) | No | State Representative | 1958 | |||
| Emanuel Cleaver (D) | No | Mayor of Kansas City, Minister | 1944 | |||
| Jeff Fortenberry (R) | No | Publishing executive, economist | 1960 | |||
| Brian Higgins (D) | Yes | Buffalo Common Councilman, State Representative, Political assistant | 1959 | |||
| Randy Kuhl (R) | No | State Representative, State Senator, attorney | 1943 | |||
| Virginia Foxx (R) | No | State Senator, college professor/administrator | 1943 | |||
| Patrick McHenry (R) | No | State Representative, realtor | 1975 | |||
| Dan Boren (D) | No | State Representative | 1973 | |||
| Mike Fitzpatrick (R) | No | Member of the Bucks County Board of Commissioners, Attorney | 1963 | |||
| Allyson Schwartz (D) | No | State Senator | 1948 | |||
| Charlie Dent (R) | No | State Representative State Senator | 1960 | |||
| Bob Inglis (R) | No | Former Congressman, Attorney | 1959 | |||
| Louie Gohmert (R) | Yes | Soldier | 1953 | |||
| Ted Poe (R) | Yes | Prosecutor, judge Harris County, Airmen | 1948 | |||
| Al Green (D) | No | Justice of the Peace Harris County, attorney | 1947 | |||
| Michael McCaul (R) | Yes | Federal prosecutor | 1952 | |||
| Mike Conaway (R) | Yes | Soldier | 1948 | |||
| Kenny Marchant (R) | Yes | State Representative | 1951 | |||
| Henry Cuellar (D) | No | State Representative, Secretary of State Texas, | 1955 | |||
| Thelma Drake (R) | No | State Representative, realtor | 1949 | |||
| Cathy McMorris (R) | No | State Representative, orchardist | 1969 | |||
| Dave Reichert (R) | No | Sheriff King County, Airmen | 1950 | |||
| Gwen Moore (D) | No | State Representative, State Senate, civic affairs specialist | 1951 |
| District | Representative | Took office | Switched party | Prior background | Birth year | ||
|---|---|---|---|---|---|---|---|
| (D) | No | White House staffer | 1944 | ||||
| (R) | No | State Representative | 1951 | ||||
| (R) | No | State Senator | 1955 | ||||
| (R) | No | U.S. House of Representatives | 1951 | ||||
| (D) | No | State Assemblyman | 1951 | ||||
| (R) | No | City Councilor | 1953 |