This study investigates the association of dietary quality with dental caries increment of 11-year-old children. A 3-day dietary record including one weekend day was completed by the subjects and their parents. The nutritional quality was evaluated using a quality index based on the eating frequency of foods recommended in food guides and divided into 8 levels. The frequency of consumption of sugary foods, liquid and solid, at and between meals was also calculated. Two oral examinations 20 months apart were made in 1983-85; each time, the quality of oral hygiene was determined by using the simplified oral hygiene was determined by using the simplified oral hygiene index of Greene and Vermillon. the dental caries increment between the two examinations was evaluated using the DMFS index. When the subjects were distributed into 3 groups according to their nutritional quality index, the mean dental caries increment had a tendency to decrease as the nutritional quality increased for the total sample as well as for boys and girls considered separately; however, the analysis of variance did not reveal any differences of statistical significance. No association was established for children in this study between frequency of consumption of sugary foods and caries increment. No association was observed between nutritional quality and oral hygiene nor between the mother's education and the children's frequency of consumption of sugary foods. Thus, in our study, children with the highest dental caries increment are not necessarily the ones having a diet of poor nutritional quality nor the ones consuming sugary foods more frequently.