Today's ruling means that Josip Perkovic will be handed over to German authorities within 10 days. The dissident, Stjepan Djurekovic, was killed in Germany, allegedly by the Communist Yugoslav secret service.
Perkovic was a ranking Yugoslav secret service official in the 1980s. He created Croatia's spy agency after the Balkan country split from Yugoslavia in the 1990s.
Croatia, which joined the EU in July, initially refused to extradite Perkovic, citing local laws banning the handover. Under EU and German pressure, Croatia amended its laws in line with the bloc's standards.