The results all but assure that President Vladimir Putin will continue to dominate Russian politics. Analysts and opposition leaders warned, however, that the country was headed for Soviet-style one-party rule.
With ballots from nearly 98 percent of precincts counted, Unified Russia -- with President Vladimir Putin as its top candidate -- held a crushing lead with 64.1 percent. The Communists trailed in second place with 11.6 percent.
Outgoing State Duma speaker Boris Gryzlov told reporters today that the results are a mandate for the continuation of Putin's policies.
"The vote has confirmed the principal idea that Vladimir Putin is the national leader, that our voters support the course he has pursued for eight years, and that this course will continue -- we can now speak about it with certainty," Gryzlov said.
Two other pro-Kremlin parties, the nationalist Liberal Democratic Party of Russia and populist A Just Russia, also made it into parliament with 8.2 percent and 7.6 percent, respectively. All other parties fell below the 7 percent barrier.
No pro-Western liberal parties won seats. Turnout was approximately 63 percent.
Pollsters say the results will give Unified Russia approximately 306 votes in the 450-seat State Duma, more than the 301 needed to initiate constitutional amendments -- and to potentially overhaul the country's political institutions to keep Putin in power. Collectively, pro-Kremlin parties are expected to control 393 seats.
The results appear to assure that the Russian president will continue to play a major role in Russian politics after his second term ends next year. Putin is constitutionally forbidden from serving more than two consecutive terms. Presidential elections are scheduled for March and a new president is due to be inaugurated in May.
But analysts say Putin is likely to take up another political role -- one that would be elevated to that of Russia's de facto leader.
Some Kremlin-watchers have suggested that Putin could rule the country as a newly empowered prime minister, with the presidency becoming a ceremonial post. Putin, however, has rejected this.
An increasing number of analysts and politicians say the most likely scenario is for power to be concentrated in the Unified Russia party leadership -- with Putin ruling through the party apparatus just like the Soviet era general secretary.
Under this scenario, both president and prime minister would take their marching orders from the party elite.
Boris Nadezhdin, a leader of the opposition Union of Rightist Forces -- which failed to win seats in the Duma -- suggested in an interview with RFE/RL's Russian Service today that Russia was headed for one-party rule.
"No doubt this is a different country now. We have returned to the Soviet Union. It is not parliament or the next president that will have real power, but the Unified Russia party," Nadezhdin said.
The months prior to the vote were marked by a massive Kremlin-orchestrated propaganda campaign presenting the election as a vote of confidence on Putin's rule.
Highly choreographed rallies across the country proclaimed Putin Russia's "national leader." Fawning television coverage sang the president's praises and warned that the West -- and particularly the United States -- was seeking to provoke a repeat of Ukraine's 2004 Orange Revolution on Russian soil and overthrow the Kremlin leadership.
Putin himself called his opponents "scavenging jackals" seeking funds from foreign embassies to destabilize Russia.
In addition to the pro-Unified Russia agitprop that swept the country through the Kremlin-controlled broadcast media, there were also widespread allegations of voter intimidation and fraud.
Communist Party leader Gennady Zyuganov said the election was the least free and fair since the breakup of the Soviet Union.
"These are the hardest elections ever, the dirtiest, and most irresponsible. If in [former President Boris] Yeltsin's time there were only two ways of mishandling voting -- intimidation and tampering with final ballot protocols -- now they have come up with at least a dozen and a half ways of how to get people to vote and deceive them," Zyuganov said.
Many state employees like teachers and doctors complained about being ordered by their bosses to vote. The election monitoring group Golos has alleged that dozens of voters reported being paid to cast ballots for Unified Russia. Some voters complained they were given ballots that were already filled out.
The European Union said free speech had been violated in the run-up to the vote, and the United States urged the Russian authorities to investigate the allegations of fraud.
The Organization for Security and Cooperation in Europe's (OSCE) main election watchdog, the Office for Democratic Institutions and Human Rights (ODIHR), did not send monitors to the election citing obstruction by Russian authorities.
A delegation from the OSCE's Parliamentary Assembly and from the Council of Europe did observe the vote, and in a statement described the elections as "not fair," adding that they did not meet "commitments and standards for democratic elections."
However, Russian electoral officials say no violations took place.
The liberal Yabloko party failed to win seats in the new Duma for the second consecutive election. Yabloko leader Grigory Yavlinsky says that despite expecting widespread falsifications, he wanted his party to participate in the elections to show their opposition to Russia's current course.
One controversial deputy from the nationalist Liberal Democratic Party of Russia will be Andrei Lugovoi, a former KGB officer and chief suspect in the poisoning death of Kremlin critic Aleksander Litvinenko in London last year. Russia has refused to hand Lugovoi over to Britain, and the Duma seat provides him with immunity from prosecution.