Abstract
The return of religion as a major player in legal context has since the last decades of the 20th century found expression on two levels: in the domestic legal system and also as a force behind public international law. This article explores the latter phenomenon by outlining the parallel existence and development of general international law on the one hand, and regional international law based on politicised Islam on the other hand, by looking at some of the instruments of the Organisation of Islamic Cooperation. What challenges are represented by international law based on Islamic ideology and how does this form of international law fit into the broader landscape of international law?