I hope that the negotiations will start at the beginning of next year, Patten said in Brussels on Tuesday after his talks with Croatia's Foreign Minister Miomir Zuzul and European Integration Minister Kolinda Grabar-Kitarovic.
He added that over recent years the European Commission had developed very good relations with Croatia, which was now at the threshold of entry negotiations.
Patten recalled that Croatia had to go on with reforms, particularly in the judiciary, as well as continue cooperating with the Hague-based UN war crimes tribunal and work on the return of refugees.
Asked to comment on recent tensions in relations between Croatia and Slovenia, Patten said the EU was aware of those tensions, and expressed hope that the problem would be solved soon in a friendly and peaceful manner.
Minister Zuzul said that Croatia would try to reach agreement with the new Slovene government on terms and conditions for arbitration which might help settle border issues between the two countries.
Zuzul and Grabar-Kitarovic on Tuesday also held talks with Jan Figel, a member of the European Commission in charge of culture, and the future Enlargement Commissioner, Olli Rehn.