Öz At the conference held on the 26th of January 2009 by the Istanbul University Faculty of Law, the concept of illegally obtained evidence was discussed from the perspective of the four legal systems represented, namely Turkey, the United States, the Netherlands and the sui generis legal system of the European Treaty of Human Rights (ETHR).1 Providing a most interesting opportunity for comparative study, the object of the Istanbul conference was to develop familiarity with the formats of this legal concept in the various systems, as well as similarities and contrasts between them.