In a sign of shifting tides, incumbent Viktor Yushchenko now lags behind Viktor Yanukovych in the polls, and along with an extensive field of 18 candidates, a run-off on Feb. 7 appears likely, some observers say. Under Ukrainian election law, a candidate needs 50 percent of the vote to win in the first round.
In the last presidential election in 2004, Yanukovych was initially declared the winner of a runoff that was later deemed fraudulent by election monitors. After daily protests, the results were nullified and the Ukrainian Supreme Court ordered a re-vote from which Yushchenko emerged the victor.
But economic difficulties and government infighting chipped away at Yushchenko's popularity, which took another nosedive when he agreed to appoint Yanukovych as prime minister in 2006.
Current Prime Minister Yulia Tymoshenko is a third major candidate. She was allied with Yushchenko during the Orange Revolution, but has had a difficult working relationship with him since.
But she and Yanukovych have been embroiled in a war of words as the presidential race comes down to the wire. Tymoshenko accused Yanukovych and his Party of Regions of planning a campaign of voter fraud.
"They have formed on a corrupt basis a puppet majority in the Central Election Commission," she said, reported the Associated Press.
Yanukovych, meanwhile, defended his decision not to participate in a televised debate with Tymoshenko by saying, "I have been debating with Tymoshenko for five years. In those five years she has not once told the truth either to me or the country as a whole," quoted Reuters.
While the popularity of key politicians might have shifted since 2004, the Orange Revolution did have some lingering effects, according to Steven Pifer, senior fellow at the Brookings Institution and ambassador to Ukraine from 1998 to 2000.
"I do think that the Ukrainian population understands that it has power now in a way that it did not understand before 2004," he said. "And I think that does constrain activities of some politicians."
In addition, Pifer said he was "fairly confident that this is going to be a good election process, because I think if some party tried to steal it through fraud and was discovered, they risk what happened in 2004.
"The more concern ought to be what happens in the run-off election, where the stakes are going to be that much higher," he continued. "But there are a lot of domestic observers and international observers, and a lot of mechanisms in place that I think would detect major fraud."