The polls have closed after Tunisia's first presidential election since the 2011 "Arab Spring" that triggered uprisings across the region.
About 54% of the electorate took part, with no reports of any violence.
Interim president Moncef Marzouki and anti-Islamist leader Beji Caid Essebsi were touted as the favourites in a field of more than 25 candidates.
Both campaigns claimed to have won the most votes but admitted that a second round of voting next month was likely.
The official results are due out later this week and if no candidate wins more than 50%, a run-off will be held on 31 December.