With 99% of the ballots counted, First Deputy Prime Minister Medvedev, 42, received 70.22% of the vote in Sunday's elections with a record turnout of 69.6% of the country's 109 million eligible voters, the Central Election Commission (CEC) said.
His nearest rival, Communist Party leader Gennady Zyuganov, was on 17.77%. Nationalist Vladimir Zhirinovsky had 9.37% of the vote and the leader of the pro-Western Democratic Party, Andrey Bogdanov, - 1.29%.
The overwhelming lead is enough to give Medvedev victory in the first round of voting.
During the 2004 presidential elections, voter turnout was 64.4%.
Election officials said that the polls had taken place without serious violations. However, critics pointed to pressure on voters to cast their ballots, especially employees at state-run organizations.
The refusal by the Russian election authorities to register a number of candidates from Russia's opposition due to 'irregularities' in their applications was also cited, as was the lack of media coverage for candidates given permission to stand.
As results came in, Medvedev's main contenders, Gennady Zyuganov and Vladimir Zhirinovsky, hinted that they could contest the election results in the courts.
Many Western observers, including the OSCE's main election arm, chose to boycott the election claiming Russia had imposed restrictions on monitors. However, Moscow has strongly rejected the allegations.
Medvedev was publicly backed by President Vladimir Putin as his successor in mid-December, and was later nominated by the ruling United Russia party as a presidential candidate.
Putin later announced that he would take up an offer by Medvedev to become prime minister, if his 'heir' was elected president.
Medvedev said on Sunday his presidency would be a "direct continuation" of the policies of the man who had backed him to lead Russia, and his future work in tandem with Putin "may bring interesting results for the country and become a positive factor in the development of our country."
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