The Third National Health and Nutrition Examination Survey-Phase 1, conducted from 1988 to 1991 in the United States, included an assessment of dental caries in US children and adolescents and provided the opportunity for differences in dental caries status to be viewed by a ge, sex, race, and race-ethnicity. The measurement of dental caries in children and adolescents from 2-17 years of age included the number of decayed, missing, and filled permanent tooth surfaces and teeth, and the number of decayed, and filled primary tooth surfaces and teeth. Additionally, a brief visual inspection for the presence or absence of early childhood caries in the maxillary incisors was conducted for children 12-23 months of age. The survey yielded weighted estimates for 1988-1991 for over 58 million US children and adolescents 1 to 17 years of age. For infants aged 12-23 months, 0.8% were scored positive for early childhood caries. Over 60% (62.1%) of the children aged 2-9 years were caries-free in their primary dentition. Over half (54.7%) of the children 5-17 years were caries-free in their permanent dentition. The occurrence of caries in the permanent dentition is clustered: A quarter of the children and adolescents ages 5 to 17 with at least one permanent tooth accounted for about 80% of the caries experienced in permanent teeth. Differences in caries experience were found among race and race-ethnicity subpopulations, and caries patterns for the primary and permanent dentition were dissimilar. Further analyses are needed to explore other potential determinants of caries in children.