The sample consists of 1,000 students who attended the seventh and eighth grades of the Rochester City schools during the 1987-1988 academic year. The students were interviewed seven times at six month intervals over the course of the study. The four peer measures were peer conventional values, peer delinquent values, peer delinquent behavior, and peer reaction to drug use. Results indicate that a substantial proportion of the students have initiated drug use, even by the time of the seventh and eighth grades. Most used alcohol and marijuana, however the rates for the use of "harder" drugs and for selling drugs were quite low. It is apparent that the friends one associates with are strongly related to one's own drug use. Associating with friends who are not strongly committed to conventional values but who are committed to delinquent values increases drug use. But most importantly, associating with friends who engage in delinquent behavior and who encourage drug use significantly and substantially increases the likelihood of using alcohol and marijuana. 4 references, 6 tables, appendix.