FACTBOX: Candidates in Russia's presidential election

(Reuters) - Russia votes on Sunday in a presidential election that is almost certain to hand victory to Dmitry Medvedev, the man President Vladimir Putin has endorsed to replace him.

Here are brief profiles of the four candidates:

DMITRY MEDVEDEV

Age: 42

Opinion poll ratings: 70-80 percent

Campaign slogan: "Forward, Russia!"

Background: Medvedev is a loyal protege of Putin. Currently Russia's first deputy prime minister, he has held the front-runner's spot since Putin endorsed him as his successor last year. His campaign has been helped by blanket television coverage. A former corporate lawyer, he will be the first Russian president with a background in business.

Promises: Stability, continuity after Putin's eight years in office. Has offered the prime minister's job to Putin. He has vowed to fight corruption and improve the rule of law. He says he wants to loosen the state's ties to big corporations, and build a knowledge-based economy to reduce Russia's dependence on energy exports.

Quote: "We are not asking anyone to love Russia, but we will not allow anyone to cause harm to Russia and we will get respect ... not with force but by our own behavior and successes."

GENNADY ZYUGANOV

Age: 63

Opinion poll ratings: 10-16 percent

Campaign slogan: "Zyuganov: our president"

Background: Zyuganov is veteran leader of the Communist Party, Russia's biggest opposition force. He appeals to voters, many of them elderly, who feel nostalgia for Soviet rule. He briefly threatened to pull out of the campaign, saying he was not being given fair access to the airwaves. His critics say he has a pact with the Kremlin to moderate his criticism, an allegation he strongly denies.

Promises: Spend Russia's oil wealth on raising pensions and wages, increase state control over the economy, boost the military, pursuit of socialism as mankind's historical destiny.

Quote: "We (the Soviet Union) were a great power and we knew how to do anything. Back then when the Chinese didn't have one serious factory, we sailed on the best submarines. We made the best airplanes. We had already reached into outer space."