Because of Russia's enormous size across 11 time zones, polling has taken 22 hours to complete.
More than 100 million Russians have been eligible to vote and indications are that just over half that number have turned up to a ballot box.
Mr Putin tops the ticket for the country's most powerful party, United Russia, and he spoke as he cast his vote in Moscow.
"People will vote for who they trust," he said.
While he is due to step down as President in March, Mr Putin is almost certain to be voted into Parliament and to continue holding immense power.
Meanwhile, the Communists say they will mount a legal challenge to the result, citing alleged voting irregularities.
Independent monitors have complained that their attempts to observe the poll were hampered. © 2007 ABC