He was taken to Basavatarakam Hospital, which he had set up with actor-politician Balakrishna, where doctors confirmed his death.
Rao, who was reportedly upset over the cases being foisted against his family members by the YSRCP.
A political slugfest erupted soon after Rao's death, with TDP leader Kesineni Nani calling his demise not a suicide albeit a "brutal murder by chief minister Jaganmohan Reddy".