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."

VLADIMIR ZHIRINOVSKY

Age: 61

Opinion poll ratings: 9-14 percent

Campaign slogan: "You will answer for everything!"

Background: Zhirinovsky is a nationalist with a knack for eye-catching stunts and blistering rhetoric, most often directed against the West. He got involved in a fist-fight during one television debate. A former colleague told Reuters he can annoy the Kremlin, but is not seen as a threat: "He is a professional actor ... in the Kremlin they understand it is just rhetoric."

Promises: Defend Russia against external enemies, ensure a strong army, provide affordable housing and support agriculture, fight corruption among officials.

Quote: "I alone am for the people."

ANDREI BOGDANOV

Age: 38

Opinion poll ratings: 1 percent

Campaign slogan: "Andrei Bogdanov: the Right Candidate"

Background: Bogdanov used to handle public relations for the pro-Putin United Russia party and critics say he retains links to the Kremlin. He dismissed this as "fantasy". His Democratic Party won 90,000 votes in last year's parliamentary election. But he was able to collect 2 million signatures in his support to qualify for the presidential vote.

Promises: Take Russia into the European Union, increase wages and pensions, army reform, fight corruption.

Quote: "Democracy in Russia will be even better than in the United States within two or three, maximum five years."

(Writing by Christian Lowe; editing by Elizabeth Piper)