This study used baseline data from the Southwest sample of the Latino Acculturation and Health Project to examine whether familism and cohesion are related to problem behaviors in a sample of Mexican and Mexican-American adolescents in the Southwest United States. This study is important to practitioners and prevention and intervention researchers because it examines buffers to problem behaviors among an increasingly at-risk population. The results confirm that familism is a powerful protective factor against aggressive behavior, conduct problems, and rule-breaking in this sample. The results draw attention to the importance of family among Mexican and Mexican-American families. Family cohesion, however, was found to be protective against conduct problems and rule-breaking but not aggressive behavior. Possible explanations for this result are discussed. Additional findings suggest that adolescents who have the ability to navigate between culture of origin and mainstream culture are also protected against some problem behaviors. (Contains 3 tables and 1 footnote.)