This article explores the impact of the First World War on the social reform movement in France, emphasizing hospital policy and medical insurance. I argue that the war gave birth to a concerted reform movement which succeeded in bringing about fundamental changes to health care policy. During the inter-war years, the French embarked on a mission to replace the traditional hospital, the maison des pauvres, with modern facilities designed to cater to the middle class as well as to the poor. In 1928, a landmark law was passed which extended medical insurance to workers and the lower middle class. By 1940, over one half of the population was covered by medical insurance, and dozens of modern hospitals had been constructed. The impetuses to this national reform legislation were the numerous local experiments, whose stories I examine in some detail. Despite the image of Third Republic ‘decadence’, the success of health policy reform during the 1920s and 1930s shows that France was indeed capable of important domestic reforms. Under Vichy, these reforms were consolidated and after the Liberation, Vichy's efforts were saluted and affirmed by French politicians.