The new head of state will be a largely ceremonial figure, but the vote is seen as a trial run for the contest between billionaire Bidzina Ivanishvili's ruling Georgian Dream party and the opposition in vital parliamentary polls set for 2020.
Georgia votes in second round of presidential election
Georgians on Wednesday voted in the second round of a presidential election seen as a crucial test for the increasingly unpopular ruling party and watched closely by Russia and the West.
In the first round on October 28, former foreign minister and ambassador to France Salome Zurabishvili failed to win more than 50 percent of the vote despite being backed by Georgia Dream. She gained 39 percent, forcing a second round.
Opposition leader Grigol Vashadze, backed by an alliance led by former president Mikheil Saakashvili's United National Movement (UNM) party, won 38 percent of the vote.
Vashadze was narrowly leading in opinion polls ahead of the second round, boosted by the endorsement of another opposition candidate who came third in the first round.
A win for Vashadze would drastically change the country's political landscape, signalling a likely end to Georgian Dream's six-year dominance.
Russia and the West watching
Western powers are closely watching the vote -- a test for the democratic credentials of the Caucasus nation that seeks EU and NATO membership.
The opposition and rights groups have accused the government of planning to rig the vote in Zurabishvili's favour.
"The outcome of the vote will determine not only who won the election, but also mark either progress or setback for Georgia's young democracy," political analyst Gela Vasadze told AFP.
Both candidates have promised to lead Georgia closer to the West, but analysts said they have different approaches in pursuing the goal.
"Both candidates have similar foreign policy priorities," analyst Vasadze said.
"But their records as ex-foreign ministers show that Vashadze is more closely associated with Washington, while former ambassador to France Zurabishvili is clearly more EU-orientated."
Vashadze's election would also likely irritate Russia, which fought a war with Georgia during the presidency of his ally Saakashvili.
"For the Kremlin, a UNM candidate's win is like a red rag for a bull and may lead to increased tensions between the two countries," said analyst Gia Nodia.
"Georgian Dream adopts a more tempered stance in its relations with Moscow, while UNM is traditionally more outspoken in its criticism of (Russian President's Vladimir) Putin's conduct in the post-Soviet space," he added.
Analyst Vasadze said that the "success of Georgia's democratic experiment will deal a blow to Putin".
"If it is possible in Russia's 'backyard' to change power through the ballot box, why is the same unimaginable in modern Russia? –- that is the question Putin does not want to hear from his citizens."
Tensions have increased after the opposition accused the government of voter intimidation and claimed that ruling party activists had attacked members of Vashadze's campaign staff.
Zurabishvili said she and her children received death threats through text and voice messages from people affiliated with the UNM.
Rights groups, meanwhile, accused government officials of vote buying on a "widespread" and "unprecedented" scale.
The Georgian Prosecutor General's office said it launched an investigation into the allegations that were flatly rejected by Georgian Dream leaders.
Vashadze, a career diplomat, has criticised Ivanishvili's "informal oligarch rule" amid growing discontent over the government's failure to tackle poverty.
Georgia's richest man, Ivanishvili, stepped down as premier in 2013 after a year in office but is still seen as the country's de facto ruler.
The vote is Georgia's last direct leadership poll as it transitions to a parliamentary form of governance.
More than 3.5 million people are eligible to vote in the election, which will be monitored by international observers from the Organisation for Security and Cooperation in Europe.
Polls opened at 0400 GMT and will close at 1600 GMT, with results expected to start being released overnight.
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