Zoo co-ordinator Gordon Glover at Winnipeg, Manitoba's Assiniboine Park Zoo said Tuesday that the bear, named Debby, was euthanized on Monday after suffering from several strokes and organ failure.
The 42-year-old polar bear was born in the Russian Arctic in 1966. She came to Winnipeg's zoo as an orphan a year later.
Debby entered the Guinness Book of World records as the oldest living polar bear earlier this year at age 41.
Few polar bears reach 20 years of age in the wild, but many have survived into their early 30s in captivity.