Welcome to the Customary IHL Database. This is the updated version of the Study on customary international humanitarian law conducted by the International Committee of the Red Cross (ICRC) and originally published by Cambridge University Press.

For more information on the Study, please see the "Customary law" section on the ICRC website.

The Database is divided in two parts:

1. Rules

This part presents an analysis of existing rules of customary IHL. While comprehensive, the Study does not purport to be an exhaustive assessment of all rules in this area of law.

This part of the Study is also available in Arabic, Chinese, French, Russian and Spanish.

A summary of the Study and the list of rules is available in many other languages.

2. Practice

This part contains the underlying practice for the rules analysed in Part 1. Rules. It is updated on a regular basis. The most recent update in July 2018 integrates national practice for two countries. Practice added in this update and the December 2017, March 2018 and May 2018 updates is marked in green.

Source materials are gathered by a network of ICRC delegations and Red Cross and Red Crescent Societies around the world.

They are incorporated into the Database by a joint British Red Cross-ICRC research team based at the Lauterpacht Centre for International Law, University of Cambridge.

International materials updated in August 2016 were incorporated into the Database by a research team at the International Criminal and Humanitarian Law Clinic, Laval University.

Translations into English of source material from non-English speaking countries are, unless otherwise indicated, unofficial translations. The authoritative version of any material translated for the Database is the original version of the document, available on the ICRC library website or upon request.