Russia's Election Commission has barred former prime minister and Kremlin critic Mikhail Kasyanov from the March presidential election.
The commission ruled Sunday that Kasyanov had tens of thousands of invalid signatures on his nominating petition.
Independent candidates need at least two million valid signatures from across the country to register to run for president.
A Kasyanov spokeswoman says the upcoming presidential election will be a farce. She says the Kremlin is scared of competition and someone with different opinions.
Kasyanov was prime minister during Russian President Vladimir Putin's first term. He was later fired and became a strong critic of the Putin government.
Russia's constitution bars Mr. Putin from running for a third consecutive term. He has endorsed First Deputy Prime Minister Dmitri Medvedev as his successor.
Opinion polls indicate Medvedev has an overwhelming lead over his rivals.
So far, the election commission has officially registered three presidential candidates in addition to Medvedev: Andrei Bogdanov, head of the Russian Democratic Party; Gennady Zyuganov of the Communist Party; and Vladimir Zhirinovsky of the Liberal Democratic Party.
Some information for this report was provided by AFP, AP and Reuters.