The head of the pan-European watchdog's Kosovo mission, Werner Almhofer, told reporters that the vote counting will be done outside of Kosovo, in the Serbian towns of Raska and Vranje.
The OSCE said it would open around 90 polling stations in the Serb-dominated northern Kosovo on May 3.
Some 11,000 Kosovo Serbs with dual citizenship are eligible to take part in the poll.
Kosovo declared independence from Serbia in 2008 and has been recognized by 90 countries, including the United States and all but five members of the European Union.
Belgrade still considers Kosovo to be a southern province of Serbia.