After years of debate, the House voted Thursday to repeal key parts of the Affordable Care Act and replace them with new provisions.
But winning approval for the bill could be even more difficult in the Senate than it has been in the House, where Republican leaders struggled for nearly two months to wrangle enough votes in their caucus to secure its passage.
The bill passed by a vote of 217 to 213, which was one more "yes" vote than was needed for passage.
All 193 Democrats voting opposed the bill. They were joined by 20 Republicans voting "no."
"A lot of us have waited seven years to cast this vote," House Speaker Paul Ryan, R-Wis., said shortly before the voting began. "Many of us are here because we pledged to cast this vote: to repeal and replace Obamacare."
"This bill delivers the promises we have made to the American people," Ryan said.
House Majority Whip Steve Scalise, R-La., told MSNBC shortly before the vote began, "We were elected to do this."
After the vote, protesters outside the Capitol building yelled, "Shame, shame!" at members of Congress walking down the front steps.
The bill — which would dramatically change the way the federal government funds purchases of individual health plans and Medicaid — is expected to dramatically increase the number of people without health insurance if enacted into law.