"I hereby resign as the member of the House of Representatives for New York's ninth congressional district effective at midnight, Tuesday, June 21, 2011," he wrote in a letter date Monday. "It has been an honor to serve the people of Queens and Brooklyn."
Weiner announced last Thursday that he would step down after he admitted sending explicit photos of himself to women.
At first, Weiner claimed his Twitter account had been hacked. He later admitted to lying and apologized but refused to step down.
Last week, he gave in to increasing pressure and resigned after 13 years in office. His congressional staff will report to the House clerk until a new representative is elected.
New York Gov. Andrew Cuomo could call for a special election any time in the coming weeks.
The Associated Press contributed to this report.