As part of a case-control study that investigated risk factors of enamel fluorosis, a fluoride/residency history was obtained covering the first six years of life by means of a mailed questionnaire, with a reliability factor of 90 percent. Of the 677 participating seventh-grade and eighth-grade children, demonstrating either mild-to-moderate dental fluorosis (fluorosis cases) or were fluorosis-free (fluorosis controls), 11 percent (N = 74) had lived in a fluoridated community for at least a year during their first six years of life. Forty percent of the fluorosis cases and 22 percent of the fluorosis controls were reported to have taken fluoride supplements during their residency in a fluoridated community, with 79 percent of the supplementation for both groups in the form of vitamins with fluoride. Further, these children had resided in more then twenty cities across ten states, and therefore do not represent just a localized problem. Such findings indicate that fluoride supplements had been incorrectly prescribed for a sizeable percentage of children residing in fluoridated areas; they also suggest an explanation for the recent increased prevalence of fluorosis in similar age-groups in some fluoridated areas. Given that the recent literature does not show that the appropriateness of supplemental prescription practices has improved for post-1975 birth cohorts, these findings suggest the need for enhanced professional education and monitoring to ensure that this occurs.