MPs adopted an amendment moved by the ruling coalition's Social Democratic Party (SDP) and Croatian People's Party (HNS) to enable President Ivo Josipovic to call that election for the same day as local elections due in May.
Under the amendment, if the two elections are held on the same day, the election for the EP can be carried out by the election commissions and committees in charge of local elections.
The election for the incumbent EP was held on 7 June 2009 and its term expires in June 2014.
Signing the Treaty of Accession to the EU, Croatia undertook to elect its first deputies to the EP in the event that the country joins the Union more than six months before the next regular election for MEPs.
The amended law will go into force on March 1 and not on the day of Croatia's EU accession.
Under the amendments, the term of Croatian MEPs begins on the day of Croatia's EU accession.
Croatian citizens will have the right to vote for the party of their choice as well as to circle also one candidate from the list of parties in election for Croatian MEPs.
The decision to call the election rests with President Josipovic, who said he would decide about it after consultations with the government, parliamentary parties, bodies in charge of elections and other relevant public officials.
The opposition believes the election of Croatia's MEPs should be held in May, on the same day as local elections.
Prime Minister Zoran Milanovic has called on all political parties to say which date they consider the best, saying the election of Croatia's MEPs can be held in April, May or June at the latest.