On August 29, 2008, the National Reference Center (CNR) for Salmonella reported to the French Institute for Public Health Surveillance the occurrence of four cases of salmonellosis caused by Salmonella Putten, a serotype that had been identified only once since 2004. The strains had been isolated between July 31 and August 12 by biological and medical testing laboratories located in the Eure, Manche, and Ille-et-Vilaine departments. A descriptive epidemiological investigation by the Western Interregional Epidemiology Unit, as well as veterinary investigations, were conducted to identify a common source of exposure and implement potential control measures. A confirmed case was defined as a person from whom the CNR Salmonella had isolated Salmonella Putten between July 15 and September 15. Probable cases presenting with diarrhea and fever (duration > 24 hours) were identified among the contacts of confirmed cases. Nine cases, including 8 confirmed cases, residing in Calvados, Ille-et-Vilaine, Loire-Atlantique, and Manche were identified during this period. The median age was 42 years [9–81]. The main symptoms were diarrhea and abdominal pain. Two cases were hospitalized. All cases had consumed fresh ground beef patties in the days preceding the onset of symptoms; 6 reported eating them raw or rare. Six cases reported purchasing the meat from stores belonging to the same chain, which was supplied with fresh ground beef by a single beef processing plant in the region. Self-inspections conducted at this plant identified the Putten serotype on fresh ground beef produced on July 24 and on ground beef sold in bulk and produced on August 6. Investigations conducted too late relative to the use-by date did not allow for the recall of the contaminated batches. This incident once again highlights that undercooked ground beef can play a decisive role in the occurrence of salmonellosis. (R.A.