People travelling to the United States will no longer have to show proof of a negative COVID test.
The change was announced by the Center for Disease Control and Prevention (CDC) on Friday and came into effect on Sunday morning.
Testing requirements for people entering the US from abroad was one of the last remaining government mandates to limit the spread of coronavirus.
According to an official, speaking under the condition of anonymity, the CDC will review testing requirements every 90 days.
President Joe Biden's government put in place testing requirements last year, as it lifted the ban on non-essential travel from several countries in Europe, as well as China, Brazil, India and Iran.
The initial requirements allowed people who were fully vaccinated to show proof of a negative test within three days of travel, while unvaccinated people had to present a test taken within 24 hours of travel.
However, the US experienced a surge in cases due to the Omicron variant and the requirements were toughened, meaning travellers had to test within 24 hours of arriving in the US, regardless of their vaccination status.
Airlines and tourism groups have been calling for the restrictions to be lifted, arguing that it is discouraging people from booking international trips.
"I'm glad the CDC suspended the burdensome coronavirus testing requirement for international travellers, and I'll continue to do all I can to support the strong recovery of our hospitality industry," the senator for Nevada, Cortez Masto, said in a statement.
The latest change comes six weeks after a federal court ended the CDC's mask requirements for mass transit, including trains, planes, buses and transit hubs, saying the agency exceeded its authority.
The Biden administration is appealing the ruling.