Medact grew out of the medical peace movement. It was formed in 1992 as a merger of two organisations: the Medical Campaign Against Nuclear Weapons (MCANW), and the Medical Association for the Prevention of War (MAPW).

After the merger of MAPW and MCANW, the newly-formed Medact recognised the need to adopt a broader global health agenda – one that would incorporate the health threats posed by climate change as well as the structural violence of unjust economic policies and systems.

Since then, Medact has been working to mobilise, support and organise health professionals to be more effective social agents for social change. A relaunch conference in 2013 marked a further milestone in revitalising Medact and confirming its future course.