Because of their ability to survive in harsh environments, including heat treatment, spore-forming bacteria, such as Bacillus spp. and kin, are prone to easily contaminate the food chain, both at the production level and during the food processing. Moreover, the spores can be reactivated (germinate) after a thermal treatment of the foodstuff, in an environment from which most other bacteria will have been eliminated. As a consequence, several Bacillus spp. can be implicated in both spoilage and contamination of a wide range of food products. In this article, a review of the main information related to the prevalence and impact of Bacilli in food is presented, with a special focus on members of the Bacillus cereus group, which are major actors in health issues, at least in foodborne toxi-infections.