This report is a summary of a longitudinal study of nonmedical drug use among university students which was carried out by members of the staff of the University of Minnesota Health Service. The study was conducted in 2 phases. The subjects in the first phase of the study were students who registered for the first time at the University of Minnesota in the fall of 1967. This first study determined the scope of the problem among entering students; succeeding investigations studied this group--minus dropouts plus transfer students--as it progressed through 4 years at the University. The 2nd investigation, that of the nonmedical drug use among college student psychiatric patients, was carried out concomitantly with the first investigation. The results of the study suggest that typical drug users: (1) may be male or female; (2) primarily smoke marijuana alone or in combination with drugs about once a week; (3) use drugs mainly out of curiosity; (4) are nonreligious; and (5) are enrolled primarily in the general college and earn grades as good as those of nonusers. (RK)