The bear was revealed by the melting permafrost on the Lyakhovsky Islands in north-eastern Russia.
With its teeth and nose intact, the bear is thought to be a species of brown bear that lived 22,000 to 39,500 years ago.
It will be studied at the North-Eastern Federal University (NEFU) in the city of Yakutsk.
Scientists at the university, known for its research into woolly mammoths and other prehistoric species, suggested the discovery was unprecedented.
Dr Lena Grigorieva, a palaeontology researcher at the university, said the bear was "the first and only find of its kind" to be recovered in once piece with "soft tissue".
"It is completely preserved, with all internal organs in place, even including its nose," Dr Grigorieva said.
"Previously, only skulls and bones were found. This find is of great importance for the whole world."
Analysis is being done to determine the age of the bear.