The protocol on cooperation in the prosecution of perpetrators of war crimes, crimes against humanity and genocide was signed by Bosnian Chief State Prosecutor Goran Salihovic and Serbian War Crimes Prosecutor Vladimir Vukcevic.
It will enable the two countries to exchange documents and information in war crimes cases and prevent suspects from escaping prosecution by seeking refuge in either country.
The protocol "represents a major step for the strengthening of regional cooperation in dealing with war crimes cases," a European official said.
The Commission said the document would also "help the process of reconciliation in the Balkans."