The Romanian Prime Minister, Victor Ponta, has conceded victory in the country's presidential run-off to an ethnic German mayor, Klaus Iohannis, reports GHN based on BBC.
"I called Mr Iohannis and I congratulated him," Mr Ponta, a Social Democrat, told reporters.
Early official results are expected on Monday. Exit polls had suggested a tight race.
Romania is one of the most corrupt EU states, something which centre-right Mr Iohannis has vowed to tackle.
Despite the election result, Mr Ponta told a local television channel that he had "no reason to resign" as prime minister.
He had hoped to become the country's youngest president, replacing the incumbent Traian Basescu who cannot stand for re-election after serving two terms.
Correspondents say the outcome of the election may have been decided by Romania's large diaspora.
Many of the four million Romanians living abroad are said to be disillusioned with Mr Ponta.
After the first round of voting, there were protests at polling stations in Paris, London, and other cities when voters had to queue for hours, with some unable to vote, leading to the resignation of the foreign minister last week.
Mr Ponta was leading in the opinion polls and had beaten Mr Iohannis, the mayor of Sibiu in Transylvania, in the first round of the presidential election.
"We are a democratic country," Mr Ponta said outside the headquarters of his Social Democratic Party on Sunday. "The people are always right."
Mr Ponta, 42, had promised to reduce the budget deficit, increase pensions and the minimum wage.
As prime minister, he oversaw economic growth and political stability in Romania, the EU's second-poorest state after Bulgaria.
Aside from tackling corruption, Mr Iohannis, 55, promised in his election campaign to strengthen the independence of the judicial system.