The 33-year-old actor was found hanging from a ceiling at his flat in Srinagar Colony late last night.
"His wife Vishita and some neighbours rushed him to Jubilee Hills Apollo hospital where he was pronounced dead," a police official said.
Deputy Commissioner of Police (West Zone) V Satyanarayana told PTI that the actor was apparently suffering from depression.
An autopsy would be carried out at Osmania General Hospital and the procedure would be video-recorded, he said. "Exact circumstances leading to the death would be known only after the probe," Mr Satyanarayana said.
Mr Kiran made his debut it the film Chitram in 2000 and followed it up with hits Nuvvu Nenu and Manasantha Nuvve, which earned him the title "Hat-trick Hero". In 2001, he became one of the youngest to receive a Filmfare award for best actor for his role in Nuvvu Nenu.
He had acted in at least 19 films, including Tamil film Poi in 2006. His last film, Jai Sriram, had released in April last year. He had also recently signed a project titled Dhil Kabbadi.
In October last year, Mr Kiran had married his long-time friend Vishita. In 2003, he was engaged to actor-politician Chiranjeevi's daughter, but the marriage was called off for unknown reasons.