The 71-year-old leader of opposition in the state assembly has requested all those who have come into contact with him to quarantine themselves.
"I have been tested positive for #Covid19 & also been admitted to the hospital on the advice of doctors as a precaution. I request all those who had come in contact with me to check out for symptoms & to quarantine themselves," Siddaramaiah tweeted.
Siddaramaiah's son Dr Yathindra Siddaramaiah said his father had a fever since Monday morning and was admitted to hospital in the night.
"He was confirmed with corona infection after the antigen test was conducted," he said in a tweet. Siddaramaiah has also been admitted to Manipal Hospital where Chief Minister B S Yediyurappa is undergoing treatment for coronavirus.
Yediyurappa was admitted to the hospital on Sunday night after he tested positive for coronavirus, and doctors have said he was "doing well" and is "clinically stable".
State Medical Education Minister K Sudhakar tweeted wishing for Siddaramaiah's speedy recovery and said he was in constant touch with Manipal hospital doctors. "His (Siddaramaiah) health is stable and there is no need to worry."