In 1982, Erdreich was elected to Congress from the 6th District, based in Birmingham, defeating one-term Republican incumbent Albert Smith, Jr.. Erdreich was re-elected four times from the urban 6th district, rarely facing serious opposition. He is among a small number of Jewish politicians to be elected to federal office from the Deep South. Erdreich was the first Democrat to represent the 6th since 1965. It was among the five districts won in 1964 by Republicans during Barry Goldwater's sweep of the state in that year's presidential election. Analysts believe that Goldwater's performance in Alabama was also related to resistance and opposition to federal passage of civil rights legislation in 1964, including the Civil Rights Act, that was disapproved of by many white residents. This was the last time a Democratic challenger defeated a Republican congressman in Alabama. In 1992, Erdreich's district was significantly redrawn as a result of a United States Department of Justice directive to create a majority-black district in the Birmingham area in order to overcome problems of voter dilution. African Americans had been divided into different districts that diluted their voting power by making them a minority in each district, preventing them from electing candidates of their choice. The state legislature failed to take action, and a federal court drew a map that shifted most of Birmingham's black residents to the 7th District. To make up for the loss in population, the 6th was redrawn to taken in several whiter and wealthier areas of Shelby and Tuscaloosa counties, areas which Erdreich had never represented while in office. Erdreich now found himself in a district that was mostly suburban and Republican, with a population that was almost 97 percent white. By comparison, his old district was urban in character, with more liberal Democratic voters, and approximately 35 percent black. Erdreich outspent his opponent, state Republican Party chairmanSpencer Bachus, almost 2 to 1, but could not overcome the more Republican bent of his new district and lost by seven percentage points. In the same election, George H. W. Bush prevailed over challenger Bill Clinton in the district by about 74 percent to 26 percent, demonstrating its conservative character. Further demonstrating just how Republican this district was, no Democratic candidate in the district has gained more than 30 percent of the vote since such time. Erdreich was known for his bipartisan work in Congress, and co-sponsored several hundred bills during his five terms. He was the lead sponsor of four bills that were signed by the president and enacted into law:
1987, , A bill to designate the new United States courthouse in Birmingham, Alabama, as the "Hugo L. Black United States Courthouse".
1990, , to redesignate the Federal building located at 1800 5th Avenue, North in Birmingham, Alabama, as the "Robert S. Vance Federal Building".
1990, , The Department of Energy Metal Casting Competitiveness Research Act of 1990, co-sponsored by the entire Alabama congressional delegation and several others.
