The US Senate has approved the most sweeping overhaul of the US tax system in more than three decades.
The House of Representatives earlier approved the bill comfortably. Republicans have majorities in both houses of Congress.
For final approval the legislation must go back to the House on Wednesday for a procedural issue.
If it passes, as expected, it will be President Donald Trump's first major legislative triumph.
Critics say the package is a deficit-bloating giveaway to the super-rich.
But Republicans argue the tax cuts for corporations, small businesses and individuals will boost economic growth.
Vice-President Mike Pence presided over the vote and announced the result.
"On this vote the ayes are 51, the nays are 48. The Tax Cuts and Jobs Act is passed," he said.
Shortly before the final tally was announced, protesters in the Senate's public gallery shouted "kill the bill". They were escorted out.
