The Election Commission said that going by preliminary data voter turnout was 60%, compared to 55.75% at the 2003 State Duma elections.
According to exit polls carried out by the Russian Public Opinion Center, United Russia gained 61%, well ahead of the Communist Party with 11.5%. The ultra-nationalist Liberal Democratic Party (LDPR) received 8.8%, and A Just Russia, led by Kremlin loyalists, garnered 8.4%.
Exit polls carried out by the Public Opinion Fund suggest an even stronger victory for United Russia, with 62.3%. The fund put the Communists at 11.8%, the LDPR at 8.4%, and A Just Russia at 8.3%.
No other parties made it past the 7% threshold needed to enter parliament.
Voting finished at 9:00 p.m. Moscow time (6:00 p.m. GMT), when the last polling stations closed in the westernmost part of Russia, the Baltic exclave of Kaliningrad.
The parliamentary elections were the fifth in Russia's post-Soviet history.