The bear matriarch lived almost twice the lifespan of free-range brown bears, which average 15 to 20 years in the wild, the zoo said on its Vkontakte social network.
The report did not specify the cause of death or when Varvara would be buried.
The ursid, a favorite among visitors, had a flashy birthday party thrown for her in June, Interfax said earlier.
She was already ailing at the time and spent most of her day resting, but still showed a healthy appetite for fruit, salmon and rabbit, the report said.
Varvara was an aspirant to the title of the oldest brown bear kept in captivity — her age at the time of death roughly the equivalent of 150 years for humans.
But she was not the all-time record holder on longevity among brown bears, known to have lived to up to 48 years in human care.
Varvara qualified for the title of world's oldest living brown bear after another Russian bear, Tikhon, died in the Penza Zoo in central Russia shortly before his 36th birthday.