Surveys suggest the 6ft 7in son of a Soviet air force colonel could win control of the city at his second time of asking. Having failed in a bid two years ago, he has enlisted the help of the former New York mayor Rudy Giuliani.
Dubbed Dr Iron Fist, Mr Klitschko, 36, turned to politics after injuries forced him from the ring in 2005, having lost only two of his 37 fights – one of them to the British world champion Lennox Lewis.
If he wins today, he has pledged to combine the two careers – making a boxing comeback while cleaning up Kiev. "We can't change the life in Kiev without breaking crime and corruption's rule," he said during the campaign.
When pro-Klitschko posters appeared around the city of 2.7 million people saying "Kiev needs a strong mayor", Oleksandr Turchynov, the candidate for the Prime Minister Yulia Tymoshenko's party, responded with his own billboards saying "Kiev needs a smart mayor".
Perhaps rattled by polls that put Mr Klitschko well ahead of Mr Turchynov and neck-and-neck with the incumbent mayor Leonid Chernovetsky, Ms Tymoshenko's party has changed tack and is now promising the boxer a top job if he falls in behind their man. "This way we may unite intellect and strength. They both have the strength and the intellect and it is necessary to unite the teams," said Ms Tymoshenko recently.
The English-language Kiev Post endorsed Mr Klitschko, citing his apparent determination to fight graft, his potential as a high-profile ambassador for the city, and his experience of life in the West during several years spent in Hamburg and Los Angeles. He also represents a striking alternative to the scandal-tainted Mr Chernovetsky, and Mr Turchynov, seen as Ms Tymoshenko's puppet.
Mr Klitschko burnished his crime-fighting credentials by touring Kiev with Mr Giuliani who, before his recent failed bid to become the Republican nominee for the US presidency, gained credit for making New York a safer city. "I will be advising Vitali Klitschko and his team on how to turn Kiev around by reforming government," he said. "He understands that reform and transparency are critical to attracting international business and sustainable economic development for his city. There will be no tolerance or room for corruption or secret dealings in a Klitschko administration."
Reflecting the striking contrasts of Mr Klitschko's world, the candidate also received a message of support from the president of the World Boxing Council (WBC), Jose Sulaiman.
"Vitali Klitschko would be the first fighting mayor in the 300-year history of boxing, and would have a great opportunity to once again become the heavyweight champion of the world," he said.
Mr Klitschko first ventured into politics by supporting the 2004 orange revolution, when protests ousted an old guard of former Communists and pro-Moscow politicians and swept into power the Western-backed liberals Ms Tymoshenko and President Viktor Yushchenko.
The leaders clashed soon afterwards, however, and a truce that helped their parties re-enter government last autumn has again given way to bitter rivalry, splitting their support in the mayoral race among several candidates.
Mr Klitschko qualified for the 1996 Olympic Games in Atlanta, but failed a drug test before the event and was withdrawn from the Ukrainian team. His younger brother, Wladimir, replaced him on the team and won a gold medal.
Vitali says he has been training for two hours each morning during the election campaign to prepare for a possible fight this autumn with the WBC champion Samuel Peter. But first he must contend with the political arena and Mr Chernovetsky – who allegedly exchanged blows with Ukraine's Interior Minister during a meeting earlier this year. "Sometimes I wish I could meet people inside the ring, where there are clear rules," lamented Mr Klitschko. "But physical power decides nothing in politics."
Source: The Independent