This study was undertaken to determine the prevalence of dental caries in children ages 6-14, from fluoridated and non-fluoridated areas in British Columbia, Canada, and the effects of receiving certain fluoride preventive procedures during childhood. Children from two communities were surveyed using a modified Decayed, Missing and Filled Tooth Surface Index (D1D2MFS). Questionnaires on the use of various fluoride preventive practices and residence histories during childhood were collected. Completed questionnaires were returned and exams were performed on 1131 children. Crude caries prevalence scores for the different fluoride exposure groups were tested for differences in dental age and the level of educational attainment of parents and/or guardians. No significant group differences were found. The 110 children with lifelong exposure only to fluoridated water had 35%, or 0.88 (S.D. = 2.91), fewer decayed or filled tooth surfaces per child (P < 0.07) than children with no reported exposure to systemic fluorides. For the 122 children who had taken fluoride supplements for 4 yr or more, 0.67 fewer decayed and filled tooth surfaces (26% reduction) were observed per child when compared to children with no exposure to fluoridated water or supplements. For children who used fluoride supplements for less than 4 yr, no significant benefits were observed. Approximately 75% of the caries prevalence for control and fluoride-exposed groups was on pit and fissured surfaces. Reductions by surface type showed savings on both smooth and pit and fissured surfaces.