Our objective was to identify the risk factors for Salmonella infection in fattening pigs in Reunion Island. Sixty pig farms were studied from April to August 2008 on the whole island. A questionnaire was submitted to the farmers, and samples of fresh faeces and gauze socks were taken to assess the Salmonella status of each herd. 40% of the herds tested positive for Salmonella spp. The most prevalent serovars were S. Typhimurium and S. Derby. The risk of Salmonella infection for the fattening pigs was increased when there was no disinfection at the farrowing stage (OR = 5.2), when large numbers of cockroaches were present on the premises (OR = 5.5) and when these facilities were not resistant to feral birds (OR = 4.5). The risk for Salmonella infection of the herd was decreased when the number of visits from technical personnel was limited (<1 per month) (OR = 0.38), when castration of piglets was done after 1 week of age (OR = 0.38) and when the all-in all-out system was respected (OR = 0.13).