They called for greater integrity in Washington, and Democrats pledge to make this the most honest, ethical, and open Congress in history.

Mr. Rangel, a 19-term congressman, has been rattled by an assortment of ethics questions since July, when The New York Times reported that a prominent developer had allowed him to lease rent-stabilized apartments, including one that he used as a fund-raising office, in violation of state regulations.

He has since been criticized for using his official stationery to solicit donations for a City University of New York school of public service that will bear his name, failing to report — or pay taxes on — $75,000 in rental income from his villa in the Dominican Republic over the past two decades and failing to disclose that the owners of the beach house had given him a mortgage on the property and waived the interest for more than a decade.

He said he would vacate the apartment he had used as a campaign office, but insisted that he had never helped — or even met — the landlord whose generosity allowed him to save more than $30,000 a year on the multiple rent-stabilized apartments.

He also said he had never used his power or public position to help any of the business leaders or foundations he had asked to support the Charles B. Rangel Center for Public Service at CUNY. Mr. Rangel also described his failure to disclose his income from the beach villa, or pay taxes on it, as an unintentional oversight by his staff, his wife and himself.

Mr. Rangel has privately discussed the idea of stepping aside temporarily, pending the outcome of a House ethics inquiry, Democrats said. But leaders are concerned that it could set a precedent in which chairmen who have not been charged criminally may be forced out of their positions.