BUCHAREST, Romania — President Traian Basescu narrowly won re-election on Monday, and with it the chance to try to lead Romania out of its economic woes, despite deep political polarization that has stymied efforts to combat the crisis.

Mr. Basescu won a second five-year term by less than a percentage point, beating back a stiff challenge from the Social Democratic candidate, Mircea Geoana, a former foreign minister. Election officials reported that Mr. Basescu, of the Democratic Liberal Party, had won 50.33 percent, compared with 49.66 percent for his opponent.

Supporters of Mr. Geoana, who on Sunday night stood before a cheering crowd and declared victory, have already charged that the election was marred by fraud. “We will begin the procedure to contest the result of the election,” said Liviu Dragnea, general secretary of the Social Democrats.

The incumbent’s victory in essence put this troubled country of 22 million back where it was in October, when the government fell in a no-confidence vote in the grip of recession and political paralysis. Analysts said they feared that political gridlock would continue.

“A perfectly divided Romania, facing the crisis, this is the story,” said Dorel Sandor, director of the Center for Political Studies and Comparative Analysis in Bucharest, the capital. “All we did was lose time, more than two months, waiting for after the election.”

And if the parties are unable to come to terms over a new government, early parliamentary elections might add to the instability.

Mr. Basescu has to ask Parliament to submit proposals for a new prime minister. Without a government, Parliament has been unable to pass a budget for 2010, an important step in negotiations with the International Monetary Fund over a $30 billion aid package to help Romania weather the economic crisis.

“I see a period of continued political instability, and unfortunately this will delay actions which would secure I.M.F. funding and which would create a foundation for future potential growth,” said Matei Paun, managing partner at BAC Investment Banking in Bucharest. “No one’s minding the store economically. That’s been the problem for six months now.”

Many Romanian factories have been idled as the recession reduced demand. At the same time, some of the estimated 2.5 million or more Romanians working abroad in countries like Italy and Spain lost their jobs and were forced to come home. A temporary freeze on state-sector salary increases led to protests and strikes.

Mr. Geoana, the challenger, ran a campaign promising to restore stability, announcing a deal with the Liberals to form a new government if he won, and promising to name a popular independent politician, Klaus Johannis, as prime minister. He was favored heading into Sunday’s vote, after leading in the final opinion surveys.

But it was the pugnacious incumbent who pulled out the victory. Mr. Basescu, a former ship captain, has made few friends in the political establishment with a tough governing style. He survived an impeachment attempt in 2007, winning a referendum intended by opponents to oust him.

Mr. Basescu, the former mayor of Bucharest, came to power five years ago promising to fight corruption. He has enjoyed successes in his term, in particular Romania’s entry into the European Union in 2007.