You wrote it, you own it.
And the Wisconsin Republican insisted that "major components" of that bill will stay in place.
Ryan's comments on Fox Business News came as conservatives and other critics of the bill, which would repeal and replace key parts of the Affordable Care Act, clamored for changes.
Some conservative allies of Trump have called for the president to drop his support for the proposal because of the political perils of shrinking federal financial aid to help people get health coverage.
"Obviously, the major components are staying intact, because this is something we wrote with President Trump, this is something we wrote with the Senate committee," Ryan said.
"This is the plan we ran on all of last year."
The Congressional Budget Office estimated Monday that the bill, if it becomes law, will result in 24 million more people becoming uninsured by 2026 than would be the case under Obamacare. The CBO also noted that lower-income and older people who buy individual health plans would tend to face sharply higher health-care costs.