This study measured the effect of a 20-week, family-centered electronic media intervention on electronic media use, body composition (dual-energy X-ray absorptiometry; DXA), physical activity and dietary behaviors in boys. Twenty-two boys were assigned and 21 were analyzed in an experimental or control group. Boys in the experimental group set electronic media use goals and used TV Allowance device and ENUFF software to reduce electronic media use. Data were collected at baseline, 10 weeks and 20 weeks. Interactions were found in daily electronic media use and DXA. At 10 weeks, step counts increased by 543 steps per day in the experimental group and decreased by 340 steps per day in the controls. Steps in both groups were higher at 20 weeks. Meals or snacks eaten while using electronic media decreased in the experimental group only. In conclusion, a family-centered electronic media intervention may reduce electronic media use and contribute to desirable changes in body composition.