Contrary to what is observed in many Western societies, the caries prevalence among children and adolescents in the Baltic States remains high. The aims of the present study were to describe the caries prevalence and oral hygiene among 7-, 12-, and 15-year-old Lithuanians and to correlate the caries prevalence with fluoride content in the drinking water, oral hygiene, gender, ethnicity, and pattern of sugar consumption. The investigation was based on cluster samples, and the clinical investigation was performed in accordance with criteria defined by WHO. High DMFT values were registered (mean DMFT = 1.3 among 7-year-olds; DMFT = 4.9 among 12-year-olds and 7.0 among 15-year-olds) and were associated with low fluoride content in the drinking water and poor oral hygiene. Girls showed higher DMFT values than boys. No correlation between pattern of sugar consumption and caries prevalence could be disclosed.