The Stanford GEMS trial was a 2-arm, parallel group, randomized controlled trial to test the efficacy of a culturally tailored after-school dance program and a family-based intervention to reduce television, videotape, and video game use to reduce body mass index gain in preadolescent African American girls with lower socioeconomic status. The GEMS Jewels After School Dance Intervention was offered for 2.5 hours 5 days per week, 12 months per year at community centers in selected neighborhoods. The intervention also included a home-based screen time reduction intervention designed to incorporate African or African American history and culture. Changes in body mass index did not differ between groups (adjusted mean difference, 0.04; 95% CI, −0.18 to 0.27 per year). Among secondary outcomes, fasting total cholesterol levels, low-density lipoprotein cholesterol levels, incidence of hyperinsulinemia, and depressive symptoms fell more among girls in the dance and screen time reduction intervention. The results indicate a need for continued solution-oriented research to identify approaches and methods that produce greater effects in population-based samples of children.