President Barack Obama will nominate Janet L. Yellen as chairwoman of the Federal Reserve on Wednesday, White House officials said Tuesday night, ending an unusually prolonged and public search to fill one of the most important economic policy-making jobs in the world.

Yellen, 67, has been the Fed's vice chairwoman since 2010, when Obama nominated her to the post and she was easily confirmed on a voice vote by the Senate. She would be the first woman to run the central bank.

She is also expected to win bipartisan support for her new role in the Democratic-controlled Senate, said Sen. Charles E. Schumer of New York. But some Republicans could throw up hurdles. Sen. Bob Corker of Tennessee voted against her appointment as vice chairman because of what he called 'her dovish views on monetary policy,' and he was already expressing reservations on Tuesday night about her nomination for the top job.

'We will closely examine her record since that time,' said Corker, who sits on the Banking Committee, which must clear her nomination before it moves to the full Senate. 'But I am not aware of anything that demonstrates her views have changed.'

Yellen's nomination was widely expected, but she was not thought to be Obama's first choice for the job. For months, the speculation was that the president would nominate Lawrence H. Summers, a former adviser of Obama's. But Summers d.