"Russia without Putin!" the crowd chanted as it protested alleged election fraud during the recent parliamentary vote that saw Prime Minister Vladimir Putin's United Russia party garner nearly 50% of the vote.
Many in the crowd said they were fed up with Putin, who served as president for eight years beginning in 2000 and is now seeking a return to the presidency in an election scheduled for March.
"In 2012, we will clear the Kremlin of swindlers and thieves." said opposition leader Garry Kasparov, a former world chess champion.
The rally was held in one of Moscow's widest downtown streets, Sakharov Avenue, named for dissident nuclear scientist Andrei Sakharov. Along the length of the street, organizers placed huge screens that displayed speeches from the platform.
Thousands of people also protested in cities and towns across Russia.
"This movement shows us that the country has changed," said Vladimir Lukin, a presidential envoy on human rights who came to the Moscow rally as an observer. "The authorities at last realized how many people want changes."
-- Sergei Loiko
Photo: Protesters against alleged election fraud fill Sakharov Avenue in Moscow. Credit: Misha Japaridze / Associated Press