"Yesterday morning, I noticed some mild flu-like symptoms," the 78-year-old President Museveni said in a statement. Tests confirmed he had contracted the coronavirus, he added.
"I have therefore, self-isolated... (and) delegated my work for today and tomorrow to Prime Minister Robinah Nabbanja," he said.
Museveni said he had only mild symptoms.
"However, I always prefer to err on the side of caution and self-isolate for now," he added.
One of the world's longest-serving leaders, Museveni has ruled the East African country with an iron fist for decades.
Once hailed as a reformist, he seized control in 1986, when he helped end years of tyranny under Idi Amin and Milton Obote.
But the former rebel leader has since cracked down on dissent and changed the constitution to allow himself to contest elections again and again.
Uganda has seen a series of crackdowns on those opposed to Museveni's rule, in which journalists have been attacked, lawyers jailed, election monitors prosecuted and opposition leaders violently muzzled.
According to Uganda's health ministry, the country has registered 170,255 coronavirus cases and 3,632 deaths since the start of the pandemic.