Representative Charles B. Rangel, chairman of the Congressional committee that writes the nation’s tax code, failed to pay an unspecified amount in federal taxes during the past five years on rental income from a villa he owns in the Dominican Republic, his lawyer said on Tuesday.

Mr. Rangel, a Harlem Democrat who is chairman of the Ways and Means Committee, has owned the beachfront house at the Punta Cana resort and club since 1988, but never declared the $75,000 in rental income he has earned either on his tax returns or on his Congressional financial disclosure form.

When Mr. Rangel’s legal advisers first acknowledged the unreported income last week, during interviews with reporters, they said his accountants had determined that he would probably owe back taxes to the city and New York State, but not the federal government.

But on Tuesday, his lawyer, Lanny Davis, said that the accountants had since revised their calculations and determined that Mr. Rangel would owe “a modest amount” to the federal government for unpaid taxes over the last five years. Mr. Davis said Mr. Rangel was likely to owe both the state and the city a similar amount over the same period. The combined total of back taxes owed to the city, state and federal governments will probably be “several thousands of dollars,” Mr. Davis said.