Parental Monitoring and Permissiveness: Effects on Mexican/Mexican American adolescent substance use In the Southwestern USA, Mexican/Mexican Americans represent one quarter to one third of the population (ACSP 2002, U.S. Census Bureau). Mexican/Mexican American adolescents report more substance offers and use than do non-Hispanic White adolescents (Marsiglia et al., 2001). Social science researchers have found correlations between rates of substance use and a number of demographic and ecological variables, including parental practices. Yet, little attention has been given in the existing literature to how Mexicans/Mexican Americans experience parental monitoring and substance use, even though this cultural group represents one of the largest minority groups in the United States. Furthermore, few studies have attempted to explore gender differences in substance use of Mexican and Mexican American adolescents. This investigation explored the relationship between parental practices and substance use among Mexican/Mexican American adolescents in the Southwest and gender differences in use and drug norms. Rather than relying on stereotypes of a homogeneous Latino culture, we aim to interpret the data that are specific to the experiences of Mexican/Mexican American adolescents and draw inferences from their experiences. The construct of parental practices is considered to be composed of three concepts: information-based monitoring, permissiveness, and injunctive norms. Information-based monitoring refers to the extent that parents are aware of their children's activities (Bahr et al., 1998). Public service announcements have been instructing parents to “Ask who, ask where, and ask when.” In contrast, parental permissiveness is the degree to which parents have requirements for their children's behaviors (Lamborn, et al., 1991), while injunctive norms refer to the perception the adolescents have concerning their parent's expectations for their behavior and parents' likely reactions to undesirable adolescent behaviors (Li, et al., 2000). This study utilizes secondary analysis of data from a randomized trial of a drug prevention curriculum tested with a sample of 3,017 Mexican/Mexican American seventh grade students in a major Southwest metropolis. The outcome measures were gathered through self-report questionnaires administered at the beginning of the randomized trial. The analysis utilized bivariate correlations, and multivariate techniques. Outcome was measured by lifetime and recent substance use, positive drug expectations, and substance use norms. Results showed that controlling for age, gender, SES, grades, and acculturation, parental monitoring is not related to actual substance use among Mexican/Mexican American adolescents, while parental permissiveness and parental injunctive norms are significantly related to alcohol, cigarette and marijuana use. However, with respect to adolescents' anti-drug expectations and norms, results were more variable and indicated interesting differences according to both gender and substance. Parental monitoring was significantly related to male's norms towards all three substances, but was only significant for female's norms towards cigarette use. Parental permissiveness was found to be significant only for female's positive drug attitudes but not for males. Parental injunctive norms emerged as the most consistent significant parental factor in explaining all of the outcomes measured. Implications for substance use prevention are discussed. Key Words: parental monitoring and permissiveness, injunctive norms, personal anti-drug norms, substance use, Mexican/Mexican American adolescents.