"We consider the December 4 parliamentary elections illegitimate and call for a boycott of these disgraceful 'elections' in every reasonable way," said a declaration signed by Kasparov and other vocal but marginalised opponents of the Kremlin.
"It's an appeal to consciously ignore cooperation with the current authorities," Kasparov, who leads the United Civil Front movement, said at a press conference.
Last month's announcement that Prime Minister Vladimir Putin will seek to swap seats with President Dmitry Medvedev in 2012 presidential elections essentially told people "that voters no longer exist in the country," he said.
"We need to put a lot of effort into pulling the country from the claws of Putin's dictatorship," he said, adding that boycotting both the parliamentary and the presidential elections would be the first step.
"The results are known in advance. Nobody has any illusions. But high participation gives legitimacy to these elections. So, the fewer people vote, the lower their legitimacy," he explained.
Besides the boycott, the opposition plans to hold protests on December 4 in central squares of several cities and call on "all honest citizens" to join them in the streets.
"Our goal is to invite people into the streets instead of the elections. We have no option left but the streets," said Left Front movement leader Sergei Udaltsov.
Not all in the opposition support the boycott strategy, with some leaders suggesting that voters participate by ruining their ballot, and some asking to vote for any party except for the ruling United Russia group that Putin heads.