According to Lt Gen V Ravishankar, who was treating him at the hospital, he had lymphoma. He was in hospital for over a month.
"Mr Rai passed away around 4 p.m. in Lilavati hospital ICU," Ravishankar told IANS via a message.
A Mangalorean, Krishnaraj is survived by his wife, son and daughter.
During his stay at the hospital, he was visited by Aishwarya's in-laws Amitabh Bachchan and Jaya Bachchan.