Washington (CNN) - Rep. Diane Watson will retire at the end of the year rather than run for re-election, three Democratic sources tell CNN.
Watson, 76, represents California's 33rd congressional district, which includes parts West Los Angles and Culver City. The four-term congresswoman won a special election in 2001and re-election to full terms in 2002, 2004, 2006, and 2008.
The district is considered overwhelmingly Democratic. Watson has won at least 80 percent of the vote in each of her re-election contests. Barack Obama took the district by 75 points in the 2008 presidential election and John Kerry won the district by 67 points in the 2004 presidential contest.
Watson's congressional office tells CNN that the congresswoman has scheduled a news conference for Thursday, but would not confirm the retirement.
Confirmation of Watson's retirement comes hours after Republican Rep. Vern Ehlers of Michigan announced that he will not run for re-election in November.
Watson will become the seventh House Democrat to retire at the end of the year rather than run for re-election, but the first from a district considered safe for the party.
Separately, Rep. Robert Wexler of Florida stepped down at the beginning of the year, to head up the Center for Middle East Peace. A special election will be held on April 13 for the seat, which is considered safe for the Democrats. Six other House Democrats are running for statewide offices rather than re-election in November.
Democratic Rep. John Murtha of Pennsylvania died on Monday. A special election will be held for his seat later this year.
Ehlers becomes the fifth House Republican to retire rather than run for re-election. Eleven other House Republicans are making bids for higher office rather than run for re-election.
Watson's retirement was first reported by CQ-Roll Call.