The Serbian parliament has given its approval for the formation of a coalition government.
Mr Kostunica agreed to the coalition last Friday
The new government will be made up of Serbia's main pro-democracy parties and led by the current acting PM, moderate nationalist Vojislav Kostunica.
The vote came just before a constitutional deadline, avoiding the requirement to call fresh elections.
Serbia's attempts to prevent independence for Kosovo is expected to be high on the government's agenda.
The UN has proposed a plan which would give Kosovo all the trappings of an independent state but the plan, broadly accepted by Albanians, is opposed by Serbia.
The province has been administered by the UN since a Nato bombing campaign in 1999 ended a Serb crackdown against ethnic Albanians, some of whom had taken up arms.
"Membership in the European Union is a clearly defined goal of this government," Mr Kostunica said ahead of the vote.
"But there will be no territorial concessions. Kosovo is a part of Serbia and it will always remain so."
Mr Kostunica said his government would also focus on co-operation with the Hague tribunal.
He added that other key issues for the new coalition will be tackling corruption and bringing in social and economic reforms.
Mr Kostunica had agreed to form a coalition with pro-Western President Boris Tadic last Friday to the relief of the West, who feared Serbia's delicate democracy would return to nationalism.
Parliament managed to approve the new government with 133-106 votes from the 250-seat house 30 minutes before the deadline expired.
But an hour before the deadline, ultra-nationalist MPs attempted to delay the vote as news emerged of a police raid in search of war crimes suspect Ratko Mladic.
Gen Mladic has been indicted for genocide by the international war crimes tribunal at The Hague.
Hardline nationalist Tomislav Nikolic said MPs had a right to know about such raids.
Talks on closer ties between Serbia and the European Union have been stalled because of lack of co-operation with the UN war crimes tribunal in The Hague.