Senate Budget Committee Chairman Kent Conrad announced today he won't seek another term next year.
Conrad (D-N.D.), who has served in the Senate since 1986, could have faced a difficult re-election race as his state has become increasingly Republican.
"There are serious challenges facing our state and nation," he wrote in an e-mail to supporters. "It is more important I spend my time and energy trying to solve these problems than to be distracted by a campaign for reelection."
CUNA's political action committee gave $9,000 to his campaign when he last won reelection in 2006 and NAFCU's PAC gave $2,000.
Conrad is the second senator to announce they are not seeking reelection next year. Sen. Kay Bailey Hutchison (R-Texas) announced her retirement last week.
In 2012 there will be 23 Senate seats being contested, 23 controlled by Democrats and 10 by Republicans.
The Senate currently has 51 Democrats, 47 Republicans and two independents who caucus with the Democrats.