The prevalence of dental fluorosis on the buccal tooth surfaces was investigated in 15-year-old children in the towns Tiel and Culemborg, using the Tylstrup-Fejerskov scoring system. A study done in 1980 revealed that at the age of six, 53% of the children in Tiel and 30% of the children in Culemborg took one or more fluoride tablets (0.25 mg F-) daily. In Tiel the tablets were provided free of charge in a centre for child dental care. On the basis of the number of tablets supplied in the age period 1.5-6 years, most of the 15 year olds in Tiel could be classified as regular, irregular or non-tablet user. Only mild fluorosis (TF-score 1, 2 or 3) was found. The percentage of children with one or more buccal surfaces affected with fluorosis was 24 in Tiel and 22 in Culemborg. The percentages of buccal surfaces with fluorosis were 6 (Tiel) and 7 (Culemborg). In Tiel the percentages of surfaces with fluorosis in the groups regular, irregular and non-tablet users were 12%, 5% and 2% respectively.