The Central Elections Commission threw the only liberal candidate - Mikhail Kasyanov, a former prime minister - off the ballot for allegedly forging signatures on his nominating petitions.
Medvedev says that if he winsو he will ask Putin to become prime minister.
Garry Kasparov, the former world chess champion and prominent Kremlin opponent, shelved his ambitions to run after his supporters were refused rental of a hall in which to hold the mandatory nominating meeting.
"It's not an election; it's a farce. Its results were known long ago," Kasparov said on Saturday after handing in a petition denouncing the vote at the election commission's headquarters in Moscow.
Medvedev's opponents are Gennady Zyuganov, head of the Communist حarty, Vladimir Zhirinovsky, an ultranationalist, and the little-known Andrei Bogdanov.
Many activists and ordinary Russians claim that workers are being pressured by bosses to vote and that some have been ordered to turn in absentee ballots, presumably so that someone else could vote in their stead.
International election observers will be barely visible.
The Organisation for Security and Co-operation in Europe (OSCE), refused to send observers, saying the Russian authorities were imposing such tight restrictions that they could not work in a meaningful way.
With Medvedev's victory virtually assured, the main political uncertainty in Russia in the transition period is whether he will be a truly independent president or essentially Putin's handmaiden.
The premiership that Putin is expected to take is the most powerful executive position in the government and Putin would be likely to maximise its influence.
Speculation persists that the parliament, overwhelmingly dominated by Putin's supporters, could expand the prime minister's powers, or that Medvedev could resign before his term is out, allowing Putin to return to the presidency.
But the president sets the government's philosophical and rhetorical tone, including its foreign policy, and the carefully spoken Medvedev so far has shown little of Putin's penchant for provocative criticisms of the West or bold assertions of Russia's reviving military might.
Medvedev did raise eyebrows recently with his comment that he could work with any US president who didn't have "semi-senile" views.
The new president's major domestic tasks hover around economic issues.
Russia has gotten rich from skyrocketing world oil prices, but the economy is hugely dependent on natural resources and needs to diversify to solidify long-term prosperity.
Inflation - more than 11 per cent last year - is undermining the nascent middle class.