President Fernandez first came to power in 1996
President Leonel Fernandez has won re-election in the Dominican Republic as his main opponent admitted defeat.
Miguel Vargas Maldonado conceded after partial results confirmed exit poll predictions giving the president a clear lead in his bid for a third term.
With more than 90% of votes now counted, President Fernandez has 53% support - enough to avoid a run-off.
"I accept and recognise the results of the elections," said Mr Vargas Maldonado, the social democrat leader.
But he refused to congratulate Mr Fernandez, saying the election had been marred by "the most shameful use of state resources".
The Organization of American States, which observed Friday's poll, said Mr Fernandez of the centrist Dominican Liberation Party, won a "clear and definitive victory".
The OAS said the election went smoothly, but noted that there were isolated incidents of violence.
The central electoral commission said Mr Fernandez had obtained 53% of the vote, after results from 99% of voting stations were tallied.
Mr Fernandez later told his cheering supporters that the first-round win meant that "no time will be lost in the continuation of our work and progress".
No figures have so far been given for the turn-out among the 5.7m registered voters.
Correspondents say Mr Fernandez is widely credited with having revived the Dominican Republic's economy during his four years in office, but has promised to do more to fight poverty if re-elected.
Unemployment is running at 16%, according to official figures, and about 25% of people live in poverty.
Mr Fernandez had earlier served as president from 1996 to 2000.
He was prevented from a new election bid at that time because of a law barring presidents from seeking second terms.
However, that law was rescinded in 2002, and Mr Fernandez won re-election two years later.