Itar-Tass did not cite a cause of death in reporting Petrov's death.
The Leningrad native wrote ballets, operas, symphonies and concertos as well as film soundtracks, theater productions and pop music, Itar-Tass said.
Petrov founded and directed the St. Petersburg Music Spring international festival.
Mikhail Baryshnikov danced Petrov's ballet, "The Creation of the World." Among his other ballets was the recent "The Master and the Margarita."
He also provided music for more than 80 films, Itar-Tass said.