One of the best studied Salmonella spp. adaptive responses is the Acid Tolerance Response (ATR), responsible for bacterial survival under extreme acid conditions, and well characterized for Salmonella enterica serovar Typhimurium. This review covers the numerous studies carried out in the last two decades describing the influence of different environmental parameters on the S. Typhimurium ATR, including the complex molecular mechanisms implicated and involvement of the ATR in virulence. The review also deals with the food safety implications of this adaptive response. Finally, the limited data available regarding the ATR of other Salmonella enterica serovars is also discussed.