Travis Childers, a Democrat who served just over two years in Congress, says he's running for the U.S. Senate in Mississippi. Primaries are June 3.
The 55-year-old Childers told The Associated Press Friday that he's qualifying for the seat that Republican Thad Cochran first won in 1978.
Cochran is challenged by two-term state Sen. Chris McDaniel in the Republican primary.
In the Democratic primary, Childers will face Bill Marcy, who has twice run unsuccessfully for the U.S. House as a tea party Republican.
Childers won north Mississippi's 1st District U.S. House seat in a 2008 special election. He was defeated by a Republican Alan Nunnelee in 2010.
The last Democrat to serve in the Senate from Mississippi was John C. Stennis, who retired in 1989.