White House press secretary Karine Jean-Pierre announced the positive test for the 81-year-old Democrat after he pulled out of a scheduled event.
"He is vaccinated and boosted and experiencing mild symptoms," Jean-Pierre said.
Biden will fly to his home in Delaware, where he will "self-isolate and will continue to carry out all of his duties fully during that time".
The president of UnidosUS, a Latino civil rights organisation, had earlier said Biden would not be able to speak at the organisation's Wednesday afternoon conference due to the diagnosis.
Dr Kevin O'Connor, the president's physician, said in a note that Biden "presented this afternoon with upper respiratory symptoms, to include rhinorrhea (runny nose) and non-productive cough, with general malaise".
After the positive COVID-19 test, Biden was prescribed the antiviral drug Paxlovid and has taken his first dose, O'Connor said.
Biden had been slated to speak at the UnidosUS event as part of an effort to rally Hispanic voters ahead of the November election.
The president had previously been at the Original Lindo Michoacan restaurant in Las Vegas, where he was greeting diners and was scheduled to have an interview with Univision.
With AP