Technical Abstract: This pilot study tested whether an Internet-based intervention could achieve change in fruit, juice, and vegetable consumption, physical activity, and self-efficacy in youth at-risk of obesity. Participants were 80 8- to 10-year-old African American girls at-risk of obesity, with a home computer, Internet access, and an e-mail address. A two-group design was followed. Groups differed only on incentive schedule (immediate, delayed). The 8-week home-based program, conducted entirely over the Internet, promoted fruit, juice, vegetables, and water intake and physical activity. Pre-post measures were collected through self-report via the program website. The study was conducted in the greater Houston, TX, area September through November 2004. Statistically significant pre-to-post differences were observed in fruit, juice, and vegetable consumption (p=.002), physical activity—yesterday (pb.001), physical activity—usually (p=.001), and fruit, juice, and vegetable self-efficacy (p=.003). Internet-based obesity prevention programs may be an effective channel for promoting healthy diet and physical activity behaviors to youth at-risk of obesity. Additional research is needed to more fully examine their effectiveness at promoting and maintaining diet and physical activity change.