This report presents the recommendations of the WHO Expert Committee responsible for updating the WHO Model List of Essential Medicines. The first part contains an update on the revised procedures for updating the Model List and the development of the WHO Essential Medicines Library. It continues to present a summary of the Committee\'s considerations and justifications for additions and changes to the 12th Model List, including its recommendation to add ten antiretroviral medicines. The annexes include the 12th WHO Model List of Essential Medicines in its usual presentation and, for the first time, in the five-level Anatomical Therapeutic Chemical (ATC) classification system.