Cigarette smoking among adolescents continues to be a major public health problem in the United States. Smoking trends from 1976-1977 to 1992-1994 were examined in the Bogalusa Heart Study, an investigation of cardiovascular disease risk factors among black and white, male and female adolescents in a semirural town in the southern United States. Age-race-sex specific chi 2 tests for trends over five survey periods were conducted. In almost every age group, black boys and girls were less likely to be current smokers or to have ever smoked or tried cigarettes, as compared with white boys and girls, respectively (P < 0.01). Within age groups, few significant trends in smoking status from 1976-1977 through 1992-1994 were observed among white boys and girls. Among black males and females, however, sharp decreases were observed among all age groups in the prevalence of having ever smoked or tried cigarettes (P = 0.0001) and among the older age groups in the prevalence of being a current smoker (P = 0.0001). Thus, substantial declines in the prevalence of smoking were observed among black children but not among white children. Further research is required to understand why these ethnic differences in smoking occurred so that public health programs may target further the smoking behaviors in children.