On June 2, 2003, the National Reference Center (NRC) for Salmonella identified 11 cases of salmonellosis caused by S. Newport, a strain resistant to multiple antibiotics, over a three-week period in northern France. The strains exhibited the same resistance profile to third-generation cephalosporins, streptomycin, sulfonamides, tetracyclines, and chloramphenicol. The article describes the epidemiological investigation conducted to assess the extent of the outbreak, identify its source, and propose appropriate control measures.