At the beginning of the war, he was assigned in a surgical ambulance automobile in the Vosges. After a short visit to Creil in a triage and regulation hospital, he was appointed to the Panthéon hospital. Then he goes to the Russian hospital in the Carlton Hotel. In April 1917, wishing for a long time return to the front, René Leriche joined Robert Proust and his team of Auto-chir (ACA n o 17). Leriche was asked by the Lyon histologist and radiobiologist Claudius Regaud to enter the training he was preparing for to serve as a "School of Medicine and War Surgery in HOE 4 de Bouleuse, near Reims.