European affairs ministers set the January 21 date after having "acknowledged reform and normalisation efforts" by the Balkan nation, the bloc's Enlargement Commissioner Stefan Fuele said.
Serbia hopes to become the 29th member of the bloc, following in the footsteps of neighbour Croatia, the newest EU member who joined in July.
Also among the six nations once part of the former Yugoslavia, Slovenia joined the EU in 2004.
"This is an historic event for Serbia, a day that many generations of citizens and numerous governments have awaited," Prime Minister Ivica Dacid said on the national RTS TV network.
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The former pariah state long sought to prise open the EU door but European leaders were insistent that Belgrade patch up ties with breakaway Kosovo, which unilaterally declared independence in 2008.
Serbia, along with five EU states, does not recognise Kosovo's independence, but under an EU-brokered Belgrade-Pristina deal in April, agreed on ways of easing the tension.
"The two sides have implemented substantially all the elements in the April Agreement," EU foreign policy chief Catherine Ashton said in a letter to EU nations this week obtained by AFP.
Opening EU entry talks with Serbia next month and continuing work to seal an EU accord with Kosovo "will provide the two sides with the necessary encouragement to continue on the path towards full normalisation," Ashton said in the document.
The latest hurdle overcome by Serbia in its drive to join the EU was a local November ballot in northern Kosovo, a longtime trouble-spot due to a Serb majority living in that region. The poll had to be re-run in early December due to tension.
About 120,000 ethnic Serbs live in Kosovo, whose 1.8-million-strong population is mainly Albanian.
In March 2011, the EU launched talks to help Belgrade and Pristina normalise relations and solve everyday problems for their citizens, such as the mutual recognition of university degrees and property records.