Hartford, Conn. ? Connecticut Gov. John G. Rowland announced his resignation Monday, as his three-term rule collapsed after revelations that he had accepted gifts worth tens of thousands of dollars from state contractors and top aides.

In a five-minute resignation speech, Rowland, a Republican, refused to say why he was stepping down. But the reasons were clear: He faced impeachment proceedings in the legislature; he is under federal investigation, and on Friday, the Connecticut Supreme Court had ruled he must testify before a House committee investigating allegations.

Rowland, 47, was the youngest mayor and congressman in the history of the state, and an unstoppable political force for much of his three terms as governor. Possessed of considerable political skills and husky good looks, the governor played a prominent role with the National Governors Assn. His name was often mentioned as a potential secretary in a second Bush Cabinet.

But for the past six months, Connecticut has been consumed by revelations about the governor’s acceptance of gifts, and there had been a steady erosion in his popularity. Rowland had allowed major state contractors and gubernatorial aides to foot the bill for a new $14,000 kitchen, a cathedral ceiling and a $3,600 hot tub at his lakeside summer cottage in Litchfield County. These same friends and associates gave the governor thousands of dollars worth of champagne, Cuban cigars and a Ford Mustang convertible.

The House committee has been having hearings in which a parade of witnesses over the past two weeks have testified about the gifts. Other disclosures included word that a friend of Rowland’s, a businessman with state contracts, had bought the governor’s Washington condominium at an inflated price.

Rowland will formally step down July 1. Lt. Gov. Jodi Rell will serve out the term that ends in January 2007.