An unusually high number of cases of Salmonella Typhimurium was reported in France in June 2008. In the course of epidemiological investigations 112 cases were ascertained, of whom 75 were interviewed. Subtyping by PFGE and MLVA identified a strain named "majority profile". Subtyping results were available for 45 interviewed cases, 30 of whom (majority below 15 years of age) were found to be infected with the majority profile strain. Evidence suggested the occurrence of an outbreak due to a monoclonal S. Typhimurium strain with the single PFGE profile XTYM-50. Cases with identical PFGE profile were also detected in Switzerland but no link with outbreaks occurring in the same period in Denmark and in the Netherlands was found. Contamination of a product distributed nationally was suggested as the cause of the outbreak but investigations did not reveal any specific food source.