Voters will elect 20 county prefects, the mayor of the capital of Zagreb, which has the same status as a county, and 555 mayors, heads of municipalities and their deputies.
The heads of counties, cities and municipalities need to collect at least 50% of the vote in the first round, otherwise there will be a run-off in two weeks' time with the first two vote-getters competing for office.
As many as 7,367 councillors and 887 deputies to county assemblies are being elected.
In counties where ethnic minorities account for more than five per cent of the local population, and in municipalities and towns where they have more than 15 per cent, the minorities will also choose deputies to local leaders from among their ranks. Minority deputies will be elected in 61 constituencies, while Croatian deputies will be elected in 14 constituencies where they constitute a minority.
Polling stations close at 7 p.m. The State Electoral Commission will report on voter turnout twice during the day, at 11 a.m. and 4 p.m.
A ban on electioneering took effect at midnight on Friday and expires after the close of polling stations at 7 p.m.