Objective: To assess the effectiveness of a dental caries prevention programme on the permanent dentition of Chilean rural schoolchildren using fluoridated powdered milk and milk derivatives. Basic research design The fluoridated products were delivered to 35,000 schoolchildren in the rural areas of the Ninth Region in Chile using the standard School Feeding Programme (PAE). The daily fluoride dose from milk fluoridated products was estimated at 0.65 mg/day, during approximately 200 schooldays/year. Cross-sectional samples of schoolchildren aged 6, 9 and 12 years from study communities and from positive control communities (ongoing APF-gel programme) were examined at the start of the study in November 1999 and after 36 months. Results No significant differences were found for the DMFT and dmft indices among 6-year-olds in the study and positive control groups either at baseline or 36 months later. Significant reductions (range 2427%) were observed in the DMFT index in 9 and 12-years-olds of the study communities when clinical data at baseline, in the absence of a fluoridated preventive programme, were compared to those obtained after 36 months of receiving fluoridated milk products. Upon the follow-up examination, the DMFT indices of schoolchildren aged 9 and 12 years old receiving fluoridated milk were not significantly different from those of the positive control comparison group of the APF-Gel programme. Conclusions Considering the relative costs and technical difficulties involved in both caries preventive programmes, it appears that in rural Chilean communities, fluoridation of powdered milk and milk derivatives is an effective alternative caries prevention programme in areas where either water fluoridation or other community delivered programmes are difficult to apply. Key words:, APF Gel programme, Chile, dental caries, milk-fluoridation programme, rural schools