Over the past decade, dental sealants have become recognized as an important adjunct to the use of fluorides in the prevention of dental caries. The most recent national survey of oral health in children conducted in 1986-1987 found that only 7.6% of children had any sealed teeth. As part of the oral health component of the 1988-1991 Third National Health and Examination Survey (NHANES III-Phase 1), the prevalence of dental sealants in children, adolescents, and adults was determined. The presence of dental sealants on posterior teeth (excluding third molars) and maxillary lateral incisors was recorded by visual and tactile methods during the dental caries examination. Findings in this paper are based on those examined persons having at least one sealable primary tooth for children aged 2-11 years (n=3,792); at least one sealable premanent tooth for persons aged 18 years and over (n=7,146). During 1988-1991, about 18.5% of US children and youth ages 5-17 had one or more sealed permanent teeth. A significantly higher percentage of non-Hispanic whites had sealants in comparison with their non-Hispanic black and Mexican-American counterparts (for all contrasts, p<0.001). As expected, molar teeth were the most frequently sealed tooth type. Only 1.4% of US children ages 2-11 had at least one sealed primary tooth. The prevalence of dental sealants decreased in the US adult population with increasing age; 5.5% of adults ages 18-24 had at least one sealed permanent tooth. Data collected from NHANES III-Phase 2 (1991-1994) will be analyzed to determine if the upward trend in sealant use continues.