This project will experimentally evaluate the efficacy of a comprehensive intervention program to prevent the development of behavioral risk factors for substance use among 970 at-risk Mexican-American and non- Hispanic children in kindergarten through grade four. In addition, the study will test a model of risk and protective factors for the development of behavioral, social, and academic problems on which the intervention is based. The model specifies that drug abuse and other problem behaviors are most likely to develop when primary grade children are aggressive and oppositional and lack academic skills. Such behavior makes poor peer relations more likely which leads to associations with deviant peers. Such associations are the most proximal social influence on drug abuse and other problem behavior. Parental discipline and monitoring are key parenting practices that influence this developmental trajectory. Family context factors such as aversive extra-familial contacts also make effective parenting less likely. Thus, a four- component prevention program is implied by this model: Family support, parenting skills training, direct instruction for children lacking critical academic skills, and behavior management to remediate aggressive and oppositional behavior in school settings. Each intervention component is based on considerable evidence for its efficacy. The validity of the model and the efficacy of the intervention will be evaluated in a randomized control trial with sufficient statistical power to examine intervention efficacy with Mexican-American children (N=297) and with non-Hispanics (N=623). In addition, structural equation modeling and latent growth analyses will test the model and examine the influence of each intervention component. The study will identify at-risk children through the Aggression scale of the CBCL (Achenbach & Edelbrock, 1983) and the Stanford Achievement Test. Families of at-risk children will be randomly assigned to receive the intervention or to participate in an assessment only control condition.