From its foundation by the British pastor Robert W. McAll, through its rapid growth in the 1870s and 1880s, and down to the contributions of some of its key figures in the twentieth century (Henri Nick, Henri Roser), this article sheds light on some of the main traits of the Mission populaire évangélique (Mission McAll) until the middle of the last century. Through its contacts with social Christianity, the Mission populaire was able to overcome some of the narrowness typical of a specific brand of Protestant Pietism with its focus on the salvation of the soul and an apolitical view of mission. As such, the Mission populaire bore rich fruit.