As of Sunday at 1 p.m. ET, Trump's approval rating has sunk to 37 percent, while those who disapprove of the president's job stands at 58 percent. His approval rating stood at 45 percent one week prior.
The Gallup poll, which measures public opinion and attitudes, and has margin of error of ±3 percentage points, also noted the economic confidence index was down 3 points to 7. Consumer spending was up $16, however, at $111.
Gallup polled about 1,500 adults nationwide.
The latest numbers came as U.S. House Republicans work on changes to the health-care bill that would repeal and replace the Affordable Care Act, better known as Obamacare. Trump has been wooing lawmakers to vote for the bill, according to Reuters.
He won the backing of a dozen conservative lawmakers on Friday after an Oval Office meeting in which the president endorsed a work requirement and block-grant option for Medicaid.
Americans also anticipate the Trump administration rolling out a major overhaul of the U.S. tax code, one of the hallmarks of the president's campaign.
White House spokesman Sean Spicer has told Ireland's Sunday Independent newspaper that the administration may not begin tax reform until late spring or the summer. Though, many don't expect to see tax reform until next year.
Trump has also been criticized for his handling of allegations of Russia ties and rhetoric surrounding global warming.
-- Reuters contributed to this report.