Apart from the incumbent head of state Ivo Josipovic, supported by the Social Democratic Party (SDP) and other parties in the ruling coalition, the other three challengers are diplomat and former minister Kolinda Grabar Kitarovic of the strongest Opposition party, the Croatian Democratic Union (HDZ), gastroenterologist Milan Kujundzic, backed by "the Alliance for Croatia" which consists of the parliamentary HDSSB party and a few nonparliamentary parties, and political activist and the youngest candidate in presidential polls so far, Ivan Vilibor Sincic, 25, supported by the civil society organisation "Human Barrier".
Ballots will be cast at 6,350 polling stations -- 6,260 in Croatia and 90 in its embassies and consulates in 50 countries, including 15 polling stations in Bosnia and Herzegovina and 13 in Germany.
As many as 22,000 observers have been registered to monitor the voting process.
The winner will be the candidate who receives a majority of votes (50% + 1 vote). If none of the four candidates musters the required majority on Sunday, a runoff will be held in two weeks' time with the first two vote-getters vying for the five-year presidential term.
The State Electoral Commission (DIP) is expected to issue preliminary incomplete results on its website at 2000 hours on Sunday and will update the information during the night.