This paper examines some aspects of islamic legal doctrine in the field of International Criminal and Humanitarian Law. I shall also consider the historical contributions made by Islamic law to contemporary international humanitarian law. My aim is to present both the classical and modern aspects of Islamic International Law denoting the new challenges facing it in today's world. The Following main questions are considered: Is there historically an Islamic International Law? What is the nature of this Islamic perspective on war crimes? What protections does Islamic law offer to civilians, prisoners of war and others in time of war? Also, does it restrict the conduct of hostilities in some way? What is the Islamic perspective on the crime of Genocide? Is Islamic law consistent with modern criminal law? Finally, what is the position of Islamic law concerning the disposition of the International Criminal Court (ICC), especially on the matter of punishment? For these purposes, in the first section we study the Islamic contribution to the public international law, then, in the second section, we will present Islamic view on the matter of International crimes especially war crimes and crime of genocide. Finally in the last section we discuss the new challenges facing Islamic law.