Updated: 12:32 p.m.

Illinois Rep. Jerry Costello (D) announced today he will not seek a 13th full term in 2012.

Costello, 62, who represents the southwestern Illinois 12th district, was first elected to Congress in a 1988 special election and he is currently the dean of the Illinois House delegation. He won his first full term with 53 percent of vote and never got under 60 percent in his subsequent elections.

“It has been a privilege and an honor to serve in the U.S. Congress for the past 23 years. However, I said when I was elected in 1988 and many times since that I did not intend to stay in Congress forever as I had other interests that I wanted to pursue,” Costello said in a statement.

“I will miss the people but not the weekly commute from home to Washington, D.C.,” he added.

Costello’s low profile in Congress earned him a perennial spot on Roll Call’s Obscure Caucus, where he appeared most recently last month.

Costello is the fifth House Member to announce he is retiring outright this cycle. Another 14 Members are running for Senate or other office. To see who else is leaving after this Congress, check out Roll Call’s Casualty List.