The senator plans to adhere to guidelines from the Centers for Disease Control Prevention, including self-quarantining for the next 14 days and alerting people with whom he may have come into contact about the diagnosis, he said.
Cassidy, 62, was tested for COVID-19 after he was informed on Wednesday that he had been exposed to an individual with the virus.
“I am strictly following the direction of our medical experts and strongly encourage others to do the same,” Cassidy said in a statement.
The Senate is on recess and is not slated to return to Washington until Sept. 8.
On Wednesday, the same day he was alerted of his potential exposure to the virus, Cassidy was visiting a veterans hospital in Shreveport, Louisiana, according to his Twitter.
Cassidy is the latest congressional lawmaker to test positive for the virus and the second U.S. senator.
So far, at least 11 members of Congress have been infected with COVID-19, according to data compiled by GovTrack.us, an organization monitoring lawmakers and their voting records.
That includes Reps. Louie Gohmert, R-Texas; Mike Kelly, R-Penn.; Mario Diaz Balart, R-Fla.; Morgan Griffith, R-Va., and Ben McAdams, D-Utah.
In late March, Kentucky Sen. Rand Paul, a Republican, became the first senator to announce that he had tested positive for the coronavirus.
A medical doctor, Cassidy was elected to the Senate in 2014.