The story usually told about the practice of enforced disappearance begins in Argentina, where Madres of the Plaza de Mayo protested endlessly against the military regime that had disappeared so many of their loved ones. But where did the Argentinian military get this idea to “disappear” its opponents? New research indicates that the origins of enforced disappearance as a state practice are based in French counter-insurgency tactics used against the Algerian resistance. This paper draws on newly conducted archival research in France and Algeria, to present findings on the development of enforced disappearance as a state security practice during the French military occupation of Algeria in the final years of that country’s war for independence.