In 2001, taking the lead from the Brahimi Report and based on consultations that took place with many practitioners involved in post-conflict locales, the United States Institute of Peace, and the Irish Centre for Human Rights, in cooperation with the Office of the High Commissioner for Human Rights and the United Nations Office on Drugs and Crime, launched the Model Codes for Post-Conflict Criminal Justice Project.

The aim of the Model Codes for Post-Conflict Criminal Justice Project is to create a set of model codes to be used as tools by both international and national actors engaged in the criminal law reform process in post-conflict states. The model codes were drafted in a way that takes into account their potential cross-cultural application and use, in addition to the inevitable exigencies of a post-conflict environment. The substantive provisions of the codes were inspired by a variety of the world’s legal systems, which were blended to create a coherent body of criminal laws tailored to these exigencies.

Beginning in 2001 to the present, the model codes were drafted in consultation with over 300 leading experts from around the world and from a variety of backgrounds. In addition, in 2004, a series of regional consultation meetings were conducted to assess both the potential compatibility of the model codes with legal systems in different regions of the world and to examine the potential utility of the model codes as a law reform tool in diverse regional contexts. An Africa roundtable was held in Abuja, Nigeria, and a follow-up meeting was conducted in London. Asian regional roundtable meetings were held in Bangkok, Thailand, and Melbourne, Australia. A meeting of Islamic legal experts was convened in Siracusa, Italy. 

The product of the Model Codes for Post-Conflict Criminal Justice Project is a set of three integrated model codes. The model codes package consists of the Model Criminal Code, the Model Code of Criminal Procedure, and the Model Detention Act.

• The Model Criminal Code is a "criminal code" or "penal code," that focuses on substantive criminal law. Substantive criminal law regulates what conduct is deemed to be criminal, the conditions under which a person may be held criminally responsible, and the relevant penalties that apply to a person convicted of a criminal offense.
• The Model Code of Criminal Procedure focuses on procedural criminal law, which is a body of rules and procedures that governs how a criminal case will be investigated and adjudicated.
• The Model Detention Act governs the laws and procedures to be applied by the criminal justice system to persons who are pending a criminal trial and also to convicted persons. Finally, the Model Police Powers Act sets out the principles, powers and duties of the police in a sphere of public safety and security. It includes provisions on such police powers as identity checks, checkpoints, security inspections, temporary restriction of movement and search and seizure. It also details conditions for the use of various types of coercive measures against individuals or a crowd and the use of force. Further, it sets out the basic principles for democratic oversight including complaint procedures for investigation of abuse of police powers.

The final element of the model codes package is a publication entitled Guidelines for Use of the Model Codes for Post-Conflict Criminal Justice. The Guidelines provide an overview of the model codes, how they were drafted, and the potential use in a post-conflict context. In addition, the Guidelines contain a synopsis of the provisions of the model codes. The Guidelines also contain a discussion on how the model codes could fit into the broader law reform process in a post-conflict state.