Republican Congressman Michael Grimm of New York announced he would resign effective Jan. 5 in a statement reported by The Associated Press and CBS.
When Grimm pleaded guilty last week to filing a false tax return, he said he would stay in Congress for as long as possible.
The Associated Press reports Grimm talked with House Speaker John Boehner before deciding to step down.
Boehner has not discussed Grimm's future publicly.
A spokesman for Boehner, Michael Steel, said in an email to The Associated Press, "We do not discuss private conversations the speaker has with members."
Grimm says he was resigning because he was not able to give the job his full attention anymore.
He would have been a distraction for Republicans — they take control of both the House and Senate when the new Congress begins its opening session on Jan. 6
House Minority Leader Nancy Pelosi had called on Grimm to resign.
Grimm pleaded guilty to tax fraud that an indictment alleges began in 2007.
The indictment accused Grimm, a retired FBI agent, of underreporting more than $1 million in wages and receipts to evade paying taxes while he was operating a small restaurant in Manhattan.
Grimm was re-elected to his Staten Island seat in November. His sentencing is scheduled for June 8.