The Supreme Court ruled on Friday that two Kurdish men wanted in Turkey for trial on terrorism charges should not be extradited by Greece.
Ankara first submitted a request for Zeki Gurbuz and Bulent Komert to be extradited in 2005.
The two men have sought asylum in Greece, claiming they are being pursued by Turkish authorities because of their political beliefs.
The court ruled that the lives of Gurbuz, 47, and Komert, 33, could be in danger if they are sent to Turkey.
The decision could be overruled by Justice Minister Antonis Roupakiotis.