Three candidates are running - incumbent President Danilo Tuerk, former Prime Minister Borut Pahor, and member of the European Parliament Milan Zver.
Most polls indicate that Tuerk could win the most votes, but not more than 50 per cent, making a round-off likely in three weeks. Various polls predict that Tuerk might win between 40 and 49 per cent of the vote, Pahor between 30 and 40, and Zver 25 per cent.
The State Election Commission will release the first incomplete results around 7.30 pm, a half hour after polling stations close, and the official results later tonight.