The bronze statue, in the city of St Petersburg, was badly damaged before dawn on Wednesday.
The statue, outside the Finland Station, marks the Bolshevik leader's return from exile in April 1917.
Lenin gave a speech at that railway station after his return from exile.
Later that year he would lead the revolution that overthrew the government and would take the Communists to power for more than 70 years.
St Petersburg was the cradle of the Russian Revolution and was renamed Leningrad after Lenin's death in 1924.
Apr 3, 2009
Bomb blows hole in rear of Lenin statue
BBC News reports that one of Russia's most famous statues of Vladimir Lenin has been bombed, leaving the Bolshevik revolutionary with a gaping hole in his rear.