The Moscow City Court on February 17 upheld sentences imposed last year against Kremlin critic Aleksei Navalny and his brother Oleg.
The court rejected calls for the Navalny brothers to be released,as well as a call by Russian prosecutors for their sentences to be increased to up to 10 years in prison.
The two were convicted of stealing 30 million rubles (nearly $500,000) from two firms between 2008 and 2012.
On December 30, a Moscow court sentenced Oleg to 3 1/2 years in prison and gave Aleksei a 3 1/2 year suspended sentence.
Aleksei Navalny demanded from the court that his brother be released from custody, saying he was used as "a hostage" by Russian authorities to impose pressure on his political activities.
Aleksei Navalny has promised to lead 100,000 people in a March 1 protest against Kremlin policies that he says are leading the country deeper into economic crisis.