The Access to Controlled Medications Programme identified the development of treatment guidelines that cover the treatment of all types of pain as one of the core areas of focus for improving access to opioid analgesics. Such guidelines are interesting both for health-care professionals and policy-makers. They are also important in improving access to controlled medicines for determining when those opioid medicines and when non-opioid medicines are preferred. Based on a Delphi study, WHO planned the development of three treatment guidelines, covering chronic pain in children, chronic pain in adults and acute pain.