Senate Majority Whip Mitch McConnell has pushed for a vote on the bill next week, but at least four Republicans have publicly voiced their opposition to the bill.
A number of other GOP senators have not committed to voting for the new healthcare bill unveiled by Republican leaders on Thursday morning.
Now he's facing his next challenge - persuading enough Republicans to back the measure. "I hope that President Trump delivers on his promise to provide more Americans with better health care for less money".
"[The Senate bill] would phase out the expansion of Medicaid that lots of states signed onto to give more people health care, beginning in 2020, and make deeper cuts after that", says Zwillich. It also would provide more generous tax subsidies than the House bill to help low-income people buy private insurance.
Shortly after the 142-page bill was distributed, more than a half-dozen GOP lawmakers signaled concerns or initial opposition.
In an interview with Fox News Channel, Trump was asked about the four conservatives opposing the bill. Obviously that means his vote could change once the bill gets amended, but it might be slightly tricky considering his reason for opposing AHCA: Medicaid. "We'll have to see".
In a statement, the American Academy of Pediatrics said, "The bill fails children by dismantling the Medicaid program, capping its funding, ending its expansion and allowing its benefits to be scaled back".
He said the bill would also jeopardize addiction treatment programs for people with opioid addictions.
The House approved its version of the bill last month. Trump later criticized the House bill privately as "mean" and this week called for a health plan "with heart".
-Congressional Budget Office analysts review the bill and its effect, both on Americans and the nation's finances.