In 1899-1900, Leriche did his military service in the 98th Infantry Regiment. He was an intern in 1902, then a doctor of medicine by supporting a thesis on the technique of surgical resection in the treatment of stomach cancer in 1906, under the direction of Antonin Poncet. In Lyon, he became friends with Alexis Carrel, whom he later meet in New York. René Leriche married Louise Héliot Calenborn on 27 September 1910 in Lyon. His wife comes from an old Germanic Catholic Family . A doctor herself, she will be his closest collaborator.