The aim of this study was to investigate the anticaries effect of fluoridated salt in a communal feeding program for preschool children. In the Gambian city of Brikama, drinking water had a low fluoride content (0.1 mg F-/L) and young children did not use toothpaste for oral hygiene. Its 2 preschools served as clusters for the trial. Random allocation of the kindergartens was performed by one person not involved in the study, and the clinical examinations were carried out using the envelope method. Meals were prepared with fluoridated salt (250 mg F-/kg salt) in the intervention group but not in the control group. According to the inclusion criteria (complete primary dentition and informed consent from legal guardian), 441 children aged 3-5 years were enrolled. The children were examined by calibrated persons according to WHO criteria, allowing the calculation of d3mft scores. The primary end point was the mean difference in the incidence of caries cavities (Δd3/4mft) after 12 months. After 12 months, the mean caries incidence per person was 1.29 d3/4mf teeth (95% CI: 0.96; 1.62) in the test group (n = 304 children) and 3.83 d3/4mf teeth (95% CI: 2.94; 4.72) in the control group (n = 137 children). Thus, the caries-prevented fraction was 66.3%. No signs of harm due to the intervention were observed. The use of fluoridated salt in a communal feeding program and in an environment with negligible availability of fluoride from other sources yields a considerable caries-preventive effect.