"I have this morning sent a letter to Speaker (Nancy) Pelosi asking her to grant me a leave of absence until such time as the ethics committee completes its work," Rangel told a news conference at which he took no questions.
The House ethics committee publicly admonished the New York Democrat last week for taking corporate-paid trips to the Caribbean in violation of the chamber's gift rules.
The panel, composed of three Democrats and three Republicans, is still looking into other matters involving Rangel, including his use of a rent-controlled apartment and his fund-raising for the Charles Rangel Center for Public Service in New York.
U.S. media, citing unnamed sources, said Rangel was encouraged to step aside before the House could vote on a Republican measure to strip him of his chairmanship, which could have happened as early as on Wednesday.
Democratic Representatives Sander Levin of Michigan or Pete Stark of California may temporarily take over as chairman, according to media reports.