The EU has approved €3bn ($3.3bn; £2.2bn) in funding to help Turkey cope with record numbers of Syrian migrants.
The organisation hopes the fund will lower the number of arrivals into EU nations.
Under the deal, the EU's executive is contributing €1bn to the fund, while the 28 member states will contribute the rest.
More than a million migrants reached the EU last year by sea, many of them travelling through Turkey.
Turkey is home to nearly three million refugees, most of them fleeing the conflict in neighbouring Syria.
A deal was struck last year between Turkey and the EU, offering Turkey funding and political concessions in return for tightening its borders.
However, financing was only secured on Wednesday after Italy dropped its objections.
Italy had questioned how much of the money should come from EU budgets but the measure has now passed unanimously.
Welcoming the move, European Commission Vice-President Frans Timmermans said: "The money we are putting on the table will directly benefit Syrian refugees in Turkey.
"I also welcome the measures already taken by the Turkish authorities to give Syrian refugees access to the labour market and to reduce the flows."