The importance of sugar in the etiology and dental caries is well known but only a few representative studies at population level have been carried out to analyze nutritional factors related to dentistry. As the main exposure to caries the frequency of the use of sugar-products should be known more exactly than we do. The purpose of this study was to analyze the frequency of consumption of sugar-containing products among Finnish adolescents. A representative sample of 3209 Finnish adolescents between the ages of 13 and 19 was drawn. The data were obtained by mail questionnaire in February and September 1977, and in February and September 1979. The separate sample was drawn in February 1978 to analyze the changes with time during 1977-79. The response rate to all the mailed questionnaires was close to 90%. The sugar-containing foods included in the study were sugar in coffee or tea, hot chocolate, pastries and cookies, soft drinks, chewing gums, sweets and pastries. In addition, the data on the consumption of artificial sweeteners were collected. According to current health behavior dogma, girls behaved better than boys. A clear relationship was observed between a householder's educational and occupational status and the children's sugar consumption. Children from homes of low social status consumed more sugar than others. The percentage of children frequently consuming sugary products decreased with improved school success. It can be concluded that the use of sugar-containing products is especially frequent among young age groups, particularly among boys from low social background and children with poor school success. Health education should be especially directed towards them.