Self-determination theory and substantial research findings suggest that more desirable outcomes may occur when participants are able to choose their prevention or treatment interventions, as having a choice may lead to greater motivation and feelings of self-efficacy. The present study examined the influence of having a choice of family-based prevention programs for youth alcohol, tobacco, and other drug use on mothers' communication outcomes. Families ("N" = 496) were those with an 11- to 12-year-old enrolled in Kaiser Permanente medical centers at one of four locations. Results from multivariate repeated measures analyses supported the importance of having a choice for improved communication outcomes. As compared with families who were randomly assigned to a program, those allowed to choose showed improved tobacco-specific and peer pressure communication, with marginally improved alcohol communication. No differences were found between the groups for general communication. Results suggest that allowing mothers to participate in decisions about health-related interventions for their teens may lead to better outcomes. (Contains 2 tables and 4 figures.)