Washington (CNN) - Democratic Sen. Kent Conrad of North Dakota will retire in 2012 rather than run for re-election.
The four-term senator announced his intentions in a e-mail to supporters.
"After months of consideration, I have decided not to seek reelection in 2012," wrote the four-term senator. "There are serious challenges facing our State and nation, like a $14 trillion debt and America's dependence on foreign oil. It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for reelection."
Conrad becomes the first of any Democrat up in 2012 to announce he will not seek re-election. Last week Republican Sen. Kay Bailey Hutchison of Texas, who's also up in 2012, announced that she would not make a bid for another term in office.
23 Democratic held seats (21 Democrats and two independents who caucus with the Democrats) are up in 2012. Only 10 GOP held seats are up for grabs.