Apart from Putin, the other seven contenders in the fray are: Sergei Baburin from the All-People's Union party; Communist Party candidate Pavel Grudinin; Civil Initiative party candidate Ksenia Sobchak; Communists of Russia party chairman Maxim Suraykin; Presidential Commissioner for Entrepreneurs' Rights Boris Titov; co-founder of the Yabloko party Grigory Yavlinsky; and head of the Liberal Democratic Party of Russia Vladimir Zhirinovsky.
Vladimir Putin has urged Russians to cast ballots in Sunday's election, which he is certain to win, saying the vote will shape the country's future.
Since first being elected president in 2000, Putin has stamped his total authority on the world's biggest country, muzzling opposition, putting television under state control and reasserting Moscow's standing overseas.
Commission chief Ella Pamfilova said: "We are immediately reacting to all claims, no matter where they come from".
A row with Britain over allegations the Kremlin used a nerve toxin to poison a Russian double agent in a sleepy English city denied by Moscow has not dented Putin's standing.
Mr Navalny said in a video posted on YouTube that "on election day, one should usually want to say 'I voted, ' but in fact I'm here to say that I didn't go to vote".
The eight presidential candidates were barred from campaigning Saturday, but the message to voters was clear from billboards celebrating Russian greatness - a big theme of Putin's leadership - and Kremlin-friendly media coverage. Disposable income rates have languished after a meteoric rise in the early 2000s, and a recent poll by the country's central bank found nearly half of Russians aren't expecting a boost to their financial situation in the next year.
Navalny has deployed more than 33,000 observers, with his team branding the vote "a staged procedure to reappoint Putin". Russia annexed Crimea from Ukraine four years ago, earning Putin admiration from many Russians and condemnation from the West.
Mr Navalny has called for a boycott of the vote.
Opinion polls give Putin, the incumbent, support of around 70 percent, or almost 10 times the backing of his nearest challenger.
In response, London expelled 23 Russian diplomats, prompting a tit-for-tat move by Moscow. We take pride in him. That'd be close to what former President Dmitry Medvedev won in 2008, when he stood in for Putin.
Critics have accused Ms Sobchak of helping Putin create a semblance of competition in the vote he is set to easily win.
Election officials flew to far-flung regions to collect votes from indigenous herders, while cosmonaut Anton Shkaplerov - the only Russian now aboard the International Space Station - cast his ballot by proxy.
In a national broadcast on TV on Friday, Putin said: "I therefore ask you to come to the polling stations on Sunday, use your right to choose a future for the great Russian Federation that we love".