EU leaders agreed on Friday to open accession talks with Serbia by January, after the country's bid was long delayed by a dispute over its breakaway region of Kosovo.
European Commission President Jose Manuel Barroso called the decision "indeed historic."
"We very often use the word 'historic' in an abusive manner, but this is historic," he told a news conference after a Brussels EU summit. "Let's not forget what happened not so long ago in that part of Europe, with one of the most violent wars we saw — and now we will start negotiations with Serbia."
More from GlobalPost: Serbia granted candidate status for EU membership
EU leaders have also agreed to launch negotiations with Kosovo for an association agreement, which covers trade and economic and political relations, and is a step toward eventual EU membership.
Serbia was long seen as a pariah because of its role in the wars that ripped through the Balkans after Yugoslavia's 1991 collapse.
The milestone decision to start the EU membership talks follows Serbia's capture of wanted war fugitives and a deal in April to mutually mend ties with Kosovo.
It also comes just 48 hours before Croatia, who fought a bitter war against Serbia in the 1990s, officially becomes the 28th EU member state. Croatia will also be the second member from former Yugoslavia, after Slovenia.