Beginning with the graduating class of 1976, each senior class was followed annually after high school until they reached 32 years of age. From about 15,000 to 17,000 high school seniors originally participating in a given class, a representative sample of 2,400 individuals was chosen for follow-up. Marijuana use was slightly lower among college students than among their fellow high school graduates of the same age. LSD and cocaine showed the largest absolute difference in drug use prevalence. College students were well below their non-college-age peers in crack use rates, and tranquilizers and barbiturates were used by fewer college students than their non-college peers. In 1997, the use of heroin during the past year by college students was less than half that by respondents not in college. Also in 1997, college students and their non-college peers had equal prevalence rates for lifetime and annual use of alcohol. Cigarette smoking among college students declined modestly during the first half of the 1980s, remained fairly stable through 1990, and then increased gradually to 28 percent in 1997. By their late 20s, two-thirds of young adults had tried an illicit drug. One in four young adults had tried cocaine by 30 years of age, 3.6 percent had tried crack, and 3.8 percent adults smoked marijuana daily. Alcohol consumption tended to increase among young adults 1 to 4 years past high school. Health implications of heavy drinking, illicit drug use, and cigarette smoking are discussed. Attitudes and beliefs of college students and young adults toward drug use and the social milieu of drug use are considered. Tables and figures