Longest-Serving Woman in Congress Is Retiring Maryland's Barbara Mikulski is stepping down from Senate By Newser Editors and Wire Services Posted Mar 2, 2015 9:07 AM CST 30 comments Comments Senate Appropriations Committee Chair Sen. Barbara Mikulski, D-Md., speaks in this 2012 file photo. (J. Scott Applewhite) (Newser) – Democratic officials say Sen. Barbara Mikulski, the longest serving woman in the history of Congress, is ready to announce her retirement. The 78-year-old Maryland Democrat, now in her fifth term, is set to make a statement at a news conference in Baltimore later today. Mikulski became the longest-serving woman in the history of Congress in 2012. She was first elected to the House of Representatives in 1976 and has served in the Senate since 1987. Mikulski is up for re-election next year, but has declined in the past to say whether she would run for what would be a sixth term. The deadline for filing is in January 2016. Mikulski is also the author of crime novels.