"My colleagues made it very clear: 'Don't even think of leaving,' " she recalled at a news conference, surrounded by women lawmakers. "I have made a decision to submit my name to my colleagues to once again serve as the House Democratic leader."
Republicans reacted with derision.
"There is no better person to preside over the most liberal House Democratic caucus in history than the woman who is solely responsible for relegating it to a prolonged minority status," said Paul Lindsay, spokesman for the National Republican Campaign Committee.
"This decision signals that House Democrats have absolutely no interest in regaining the trust and confidence of the American people who took the speaker's gavel away from Nancy Pelosi in the first place," he said.
The announcement was one of several throughout the day that would give more clarity to the leadership and direction of the next Congress, led by majority Republicans in the House and Democrats in the Senate. Voters in last week's elections gave Obama a second term, added two seats to the Senate Democratic majority and as many as eight to Pelosi's caucus in the House.
Newly-elected Sen. Angus King, Maine Independent, announced that he will caucus with Democrats next year, adding to Pelosi's announcement another question answered about the makeup of the next Congress. Leadership elections were set Wednesday for Republicans in the House and for both parties in the Senate.
Pelosi put off her caucus' leadership elections off until after Thanksgiving.
Pelosi, 72, has represented a San Francisco area district in the House for a quarter century, including a stint as the first woman in history to serve as speaker. The tea party-fueled political wave of 2010 forced the gavel from her hand to Ohio Republican Rep. John Boehner's.
Holding a news conference Wednesday morning, Pelosi said "we're very, very proud" of how large a role women played in the Nov. 6 election.
"We don't have the gavel" of majority status in the House, she said, "but we have unity."
"Being actively involved in politics at this level is really insatiable," Pelosi told reporters. "There's so much more I want to do, I don't know how to get any more hours in the day. You can only sleep so less."
Pelosi was a major force behind the passage of Obama's health care overhaul and the Lilly Ledbetter Fair Pay Act. Even after the 2010 elections, when her party lost 63 seats, Pelosi was reelected Democratic leader by her caucus.
Pelosi's colleagues had said for days that the top leadership post was hers if she wanted it in the next Congress that begins in January. She refused to reveal her plans for a week after the Nov. 6 elections failed to give Democrats gain they wanted.
It was a disappointing, but not unexpected result of a bitter year of elections that focused on the tight contests for president and control of the Senate. Throughout, Pelosi raised millions of dollars for Democratic House candidates and insisted that the 25 seat gain was within reach. But in the end, Democrats will gain at most eight seats and Republicans will keep their majority.
Waiting in the wings of Democratic ranks are Pelosi's deputy, Democratic Rep. Steny Hoyer of Maryland, the party whip, whom she has known since they were congressional interns, and South Carolina Democrat James Clyburn, assistant to the Democratic leader.
Pelosi is the daughter and sister of former Baltimore mayors. Her father, Thomas D'Alesandro, Jr., served as mayor of Baltimore for 12 years after representing the city for five terms in Congress. Her brother, Thomas D'Alesandro III, also served as mayor.
Associated Press writers Alan Fram, Henry C. Jackson and Kevin Freking contributed to this report.