In 1979, the dental health program of the New Mexico Health and Environment Department began a school-based sealant activity. Children in the first, second, third, sixth, and seventh grades in selected New Mexico communities were offered sealants through this sealant activity. During the 1984-85 school year, program staff began seeing several hundred sixth-grade students who had received sealants in either the first, second, or third grade. Tooth- and surface-specific data on the current condition of all the previously sealed occlusal surfaces were collected from all these previous recipients of sealants. During the 1985-86 school year, we found that sixth-grade students who received sealants as first, second, or third graders had 5.6 percent of the occlusal surfaces of their first permanent molars either decayed, missing, or filled. Their classmates who had not previously received sealants had 26.85 percent of the same tooth surfaces either decayed, missing, or filled. During the 1985-86 school year, the complete retention rates for sealants were found to be 67.36 percent after six years, 78.53 percent after five years, and 93.47 percent after one year. The partial retention rates were found to be 10.46 percent after six years, 10.63 percent after five years, and 3.04 percent after one year.