Interviewed 136 families with sons in the 7th and 10th grades to investigate the role of deviant peers, parent childrearing practices, and parent alcohol use in the initiation of marihuana use and alcohol use during adolescence. Analysis of the data indicated significant standardized coefficients for deviant peers predicting alcohol use and for both parental monitoring and deviant peers predicting marihuana use. Delinquent drug users had lower parental monitoring and more deviant peers than nondelinquent drug users or abstainers.