Serbian voters have approved a new constitution asserting that Kosovo is an integral part of the country.
Kosovo Serbs were delighted at the referendum result
Preliminary results show 51.5% of the total electorate backed the constitution, passing the 50% threshold needed to validate the referendum.
However, ethnic Albanians in Kosovo, which has been under UN control since 1999, ignored the poll. UN-sponsored talks on Kosovo's status continue.
Elections are now expected in Serbia before the end of the year.
Once the result was clear, Prime Minister Vojislav Kostunica said: "This is a great moment for Serbia.
"By defending Kosovo, we are defending something more than our interests, more than the issue of stability in the region," he went on.
"We are defending international law."
BBC correspondent Nick Hawton said despite broad political consensus in support of the constitution, and a strong publicity campaign, there had been little enthusiasm among the public about the referendum.
The constitution is Serbia's first following the break-up of Yugoslavia.
"I expect new elections after this referendum," said President Boris Tadic.
"I expect after those elections to see a very strong democratic majority and a democratic government which is going to lead Serbia to the European Union."
Serbia became an independent country earlier this year when its union with neighbouring Montenegro was formally dissolved.
About 6.5 million people were entitled to vote in the national referendum. The referendum was held over two days in an effort to attract as many voters as possible.
PM Kostunica spoke of "defending international law"
Among the constitution's 200 articles are guarantees for minority and human rights and the granting of a form of self-rule for the province of Vojvodina.
It also calls for the end of the death penalty - and a ban on human cloning.
"It is a new beginning in the sense that in article one it states that Serbia is a state which is based on European standards and values," senior government adviser Vladeta Jankovic said.
"[This] is an expression of our commitment to the European Union and our hope to join it in the foreseeable future," he added.
Kosovo Albanians, who make up around 90% of the province's two million population, were not able to vote as they were not included on voters lists after boycotting Serbian elections since 1990.
"No-one in Kosovo is paying any attention to the referendum," ethnic Albanian lawyer Azem Vllasi told AFP news agency.
"Moreover, its outcome cannot in any way prejudice a solution to the final status of Kosovo," he said.
The new constitution pre-empts UN-backed talks on the status of Kosovo, which are meant to draft a settlement by the end of this year.