Voters in Croatia are electing members of the European Parliament for the first time.
The 12 victorious candidates will take their seats after the Balkan nation becomes the newest member of the European Union on 1 July.
Some 3.7 million people are eligible to vote in what officials have described as a "historic" vote after a 10-year journey to EU membership.
But analysts say turn-out may be low as the country struggles with recession.
Croatia will be the second independent country from within the former Yugoslavia to join the EU, after Slovenia.
The European Commission gave the green light to Croatia's membership last month.
But the economy has been mostly in recession since 2009, unemployment has been rising and two ratings agencies have downgraded the country's debt to "junk" status.
The BBC' Balkans correspondent Guy De Launey says that the prospect of membership was previously a matter of great national pride to Croatians.
But enthusiasm for the election is at best lukewarm, he says, as joining the EU is not guaranteed to make matters better and may expose local businesses to increased competition.
Croatians just have to look next door to Slovenia, which is also facing economic difficulties, to see that EU membership is no panacea, our correspondent adds.
The elected MEPs will only serve for a year, before fresh polls are due across the whole EU.