Rules and principles of due process in criminal law--how to, and how not to, investigate crime and criminal suspects, prosecute the accused, adjudicate criminal cases, and punish the convicted--appear in the traditional sources of Islamic law: the Quran, the Sunna, and classical jurisprudence. But few of these rules and principles are followed in the modern-day practice of Islamic criminal law. Rather, states that claim to practice Islamic criminal law today mostly follow laws and practices of criminal procedure that were adopted from European nations in the twentieth century, without reference to the constraints and protections of Islamic law itself. To enforce Islam's criminal prohibitions and punishments without recognizing and heeding its own procedural rules and principles is to prosecute and punish unjustly. What constitutes criminal due process from an Islamic perspective must therefore be identified, articulated, and enforced. The result would be greater compliance with both Islamic norms and international standards of human rights.