Kasparov, who got 379 of 498 votes at a national congress of the Other Russia coalition, has been instrumental in uniting liberals, leftists and nationalists who are opposed to President Vladimir Putin.
Kasparov's candidacy now needs to be registered.
Observers, while saying his candidacy is likely to be rejected, added that even if he gets to run for President, Kasparov will be no match for whoever Putin backs.
Kasparov, who was one of the six candidates who had won Other Russia's regional primaries in recent months, will also be one of the three candidates who will head the coalition's list in parliamentary elections in December.
Rediff News Bureau | Photograph: AFP/Getty Images