A Moscow city police spokesman confirmed that Manana Javelia died on December 2 in a detention center in the Russian capital.
Human rights activists said Javelia, who had been held behind bars for nearly two months, had been denied proper medical care.
Moscow prosecutors said they had opened a probe into the death.
It is the second such death since Moscow began deporting hundreds of Georgians for allegedly breaking immigration rules.
Russia also imposed economic sanctions on Georgia following a spy scandal in September.
(civil.ge, Rustavi 2, AP)
Moscow And Tbilisi
Russian military hardware being withdrawn from a Russian base in Batumi, Georgia, in August 2005 (TASS)
WHAT COMES NEXT? Although Russia is unlikely to push an aggressive military response to the current tensions with Georgia, it has a number of economic, political, and diplomatic options at its disposal. Already on October 1, Russian President Vladimir Putin summoned his inner circle to weigh Moscow's options... (more)