WASHINGTON — Senator Robert Menendez of New Jersey was indicted on bribery charges on Wednesday in what prosecutors said was a scheme to trade political favors for luxury vacations, golf outings, campaign donations and expensive flights.

The indictment, the first federal bribery charges against a sitting senator in a generation, puts Mr. Menendez’s political future in jeopardy. He faces a possible sentence of 15 years in prison for each of the eight bribery counts.

Mr. Menendez, a Democrat, angrily denied wrongdoing and vowed to fight the charges. “This is not how my career is going to end,” he said at a news conference in Newark, where supporters cheered him. “Today contradicts my public service career and my entire life.”

The federal investigation into Mr. Menendez, 61, was well known, and charges had been expected. But the accusations in the 68-page indictment are much broader and more severe than had been publicly known. The senator was also charged with conspiracy and making false statements.