Senator Harry Reid expects the House of Representatives to approve the bill.
The Senate has approved a new version of a $700bn (£380bn) rescue plan for the troubled US financial system.
Senators voted 74 to 25 in favour of the emergency legislation, which is designed to buy up bad debts and stabilise financial markets.
It includes tax breaks for families and businesses, among other measures designed to win over sceptics.
The plan will now go before the House of Representatives, which narrowly rejected a similar bill on Monday.
President George W Bush praised Senate leaders for making "vital improvements to the rescue package" and urged the House to approve the measures.
News of the Senate vote failed to lift Asian markets. Japan's main Nikkei index ended down 1.9% and Australian stocks lost 0.6%, on wider fears about economic growth. But shares in London, Paris and Frankfurt opened up.
The original bill was criticised for pandering to the needs of Wall Street bankers at the expense of ordinary citizens.
CHANGES TO BILL
Raises government's guarantee on savings from $100,000 to $250,000
Tax breaks to help small businesses and promote renewable energy
Expansion of child tax credit and help for victims of recent hurricanes
The $700bn is designed to be used to buy up devalued assets from struggling firms to help kick-start the economy.
Since the House rejected the bill, politicians have added sweeteners such as tax breaks for small businesses and an increase in the amount of savings the state will guarantee - from $100,000 to $250,000.
The House is expected to vote again on the bill on Friday, and President Bush was keen to stress that the package was "essential to the financial security of every American".
"The American people expect - and our economy demands - that the House pass this good bill this week and send it to my desk," he said.
Treasury Secretary Henry Paulson, the architect of the initial bill who has been criticised over its failure, sounded buoyed by the Senate vote.
"This sends a positive signal that we stand ready to protect the US economy by making sure that Americans have access to the credit that is needed to create jobs and keep businesses going," he said.
US presidential hopefuls John McCain and Barack Obama, who both returned from the campaign trail for the debate, voted in favour of the rescue plan.
Both presidential candidates turned up for the vote
Senate majority leader Harry Reid, a Democrat, said he was happy with the result and praised both presidential candidates for voting.
"I think it shows that when we work together we can accomplish good things," he said.
Mitch McConnell, leader of Republican senators, was also in jubilant mood.
"This was a measure that was much needed, to unfreeze the credit markets and get America's economy working again," he said.
But the BBC's Jonathan Beale, in Washington, says the bill has passed only the first hurdle, and such celebrations could yet prove to be premature.
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