Romania's center-left prime minister, Victor Ponta, will face a conservative city mayor in a presidential runoff.
Final results from the November 2 first round show Ponta ahead with 40 percent, followed by Liberal Party leader Klaus Iohannis, the ethnic German mayor of Sibiu, with 30.5 percent.
The winner of a November 16 runoff will replace center-right President Traian Basescu, who is leaving office after 10 years in power.
Romania joined the European Union in 2007 but remains its second-poorest state and is plagued by corruption.
Ponta, who often feuded with his bitter rival, Basescu, thanked voters on November 2, accusing the outgoing president of "division."
However, without the check on power hitherto provided by Basescu, the ascent of Ponta, who heads the ex-communist Social Democrats (PSD), has raised concerns that he might put political pressure on the judiciary and anticorruption prosecutors.
Ponta's attempt to have Basescu impeached in a 2012 referendum drew sharp EU and U.S. criticism.
The center-right Iohannis told a news conference late on November 2 that he is the only one who can ensure an independent judicial system.
Iohannis is widely crediting with modernizing the Transylvanian city of Sibiu, in central Romania.
Thousands of expatriate Romanians could not vote on November 2 at embassies in London, Munich, and Paris because of what they said was the government's intentional procrastination of the voting process.
Hundreds of people protested outside Romania's Foreign Ministry in Bucharest on November 2, calling for the resignation of Foreign Minister Titus Corlatean, while in Paris, French police had to intervene to calm some 1,000 Romanians who were demanding an extension of the voting time.
The more than 3 million Romanians living in Europe and North America traditionally vote center-right and their ballots could tilt the election toward Iohannis.