A presidential runoff is expected on May 20, as both nationalist Tomislav Nikolic and incumbet President Boris Tadic are unlikely to get more than 50 percent of today's first round vote.
Serbs voted in large numbers in general elections Sunday that gave them a sharp choice between a pro-Western government or one that would bring back to power former nationalist allies of the late Balkan strongman Slobodan Milosevic.
The election for president, Parliament and local authorities will determine the pace of Serbia's European Union-demanded economic and social reforms, after facing international isolation as a pariah state under Milosevic in the 1990s for his warmongering policies.
The ballots also could determine whether Serbia continues to reconcile with its neighbors and wartime foes, including the former province of Kosovo which declared independence in 2008. Milosevic recruited nationalist paramilitaries for his wars in Croatia, Bosnia, and Kosovo in the 1990s that killed more than 120,000 people and left millions homeless.
The two leading contenders in presidential and parliamentary elections are Boris Tadic and his pro-EU Democratic Party, and Milosevic's former ally Tomislav Nikolic, whose right-wing populist Serbian Progressive Party has capitalized on EU's economic troubles, which have dimmed the bloc's allure for many Serbs.