Senators voted 64 to 35 to pass the bill, which delays the cuts for one year, in a vote that came after House Republicans used a rare voice-vote to get the measure through the lower chamber with enough support.
President Obama is expected to sign the bill into law before midnight, when the reimbursement cuts were set to go into effect.
The "doc fix" is the latest incarnation of a bill passed frequently by Congress -- sometimes multiple times a year -- that prevents a sharp drop-off in Medicare payments.
"I’m pleased that we’ve been able to come to an agreement to vote today on a 12-month fix to the Medicare physician payment system. We need to take action on this to ensure that Medicare patients will be able to see their doctors," Senate Majority Leader Harry Reid said Monday in a speech on the Senate floor. "But the fact remains that the agreement we have in place is not ideal ... Regrettably, we just don’t have the votes right now to fix this problem for good."
In 1997, Congress created the Sustainable Growth Rate (SGR), a system that pegged the amount of money budgeted for Medicare payments to projected growth of the economy. However, within a few years, health-care costs far outpaced economic growth -- creating a multibillion-dollar shortfall in funding for Medicare payments.
Since 2003, Congress has approved "doc fix" bills that appropriate more money to Medicare funding in order to avoid cuts in the Medicare reimbursement rates for doctors.
The last doc fix bill expired on March 31, forcing Congress to either pass another doc fix, pass a bill overhauling Medicare payments, or see skyrocketing costs of doctors who treat Medicare patients.
This year's doc fix bill, which prevents a 24 percent cut in reimbursements to physicians under Medicare, comes despite efforts led by Sen. Ron Wyden (D-Ore.) to broker a bipartisan agreement to permanently scrap the SGR system.
"We'll punt, patch it up and let that SGR limp along just as it has year after year," Wyden conceded during a floor speech prior to the vote on Monday. "Every senator that I talked to says that that just defies common sense."
Wyden voted against the one-year "doc fix" extension.
Democratic aides and Wyden allies have insisted, however, that his efforts this year will not be entirely in vain, and that the progress made toward scrapping the SGR could lead to a fix to the broken Medicare funding system sometime next year.