"I think that we can congratulate each other on this important stage in our history," Josipovic said on Friday in Ljubljana where he was attending ceremonies marking the 20th anniversary of Slovenia's independence.
This day is indisputably historic. However, Croatia should now continue with reforms, Josipovic told Croatian reporters in Ljubljana.
"I always emphasise that regardless of the success of the reforms implemented so far, there are many other things that we must do, not only because of the European Union but also because of ourselves," he said.
"I am sure that the closing of the negotiations will be wind in the sails of Europeanism in Croatia," Josipovic said.
It will also facilitate efforts to prepare in the best possible manner a referendum on Croatia' EU membership so that its outcome is convincing, he said.