The British leader was taken to a London hospital on Sunday evening with what were called “persistent symptoms” – including running a temperature.
The hospitalization is said to be a “precautionary step” taken on the advice of his doctor.
The Prime Minister remains in charge of the government, but British Foreign Secretary Dominic Raab is expected to chair a coronavirus meeting on Monday morning.
In a statement, a Downing Street spokeswoman said “On the advice of his doctor, the Prime Minister has tonight been admitted to hospital for tests.
“This is a precautionary step, as the Prime Minister continues to have persistent symptoms of coronavirus ten days after testing positive for the virus.”