Epidemic increases in obesity in the United States have focused research attention on prevention and treatment issues. Rates of obesity have steadily increase over the past 20 years. Adult and child obesity rates have both increased. The percentage of children at risk for overweight (at or above the 85th percentile body mass index for age) increased significantly from 28.2% to 33.6% between 1999 and 2004. One out of every three children in the United States is overweight or obese. Much effort is now focused on prevention of obesity. However, varied results have been demonstrated. Data analyzed as part of this dissertation were collected during a pediatric obesity treatment trial ("Childhood Obesity Treatment: A Maintenance Approach") funded by a five-year grant from the National Institute for Child and Human Health Development. Over a three year period (three fall cohorts), overweight children (aged 7-12 years), along with one obese parent were invited and agreed to participate in the 20-week weight loss phase of the Family Weight Control and Prevention Program in San Diego, California. This study sought to examine predictors of short term weight loss or stabilization among overweight children enrolled in this family-based behavioral intervention. Offered is an examination of areas to be considered when designing a weight loss intervention program and evaluating what components to maintain as part of an overall program while attempting to reduce participant burden. First evaluated was whether demographic variables affected outcome in an intervention targeting overweight children. Race/ethnicity and socioeconomic status were not found to have a differential effect on the amount of weight lost or self-efficacy. This suggests that intervention strategies don't always need to be tailored to race/ethnicity or socioeconomic status. Next evaluated was dietary self-monitoring. As found previously among adults and adolescents, preadolescent children who completed journals on a more consistent basis, lost more weight comparatively. Additionally, any self monitoring was beneficial for weight loss when compared to those who did not journal. Finally, we demonstrated that physical activity self-efficacy is an important variable to consider in the planning of exercise programs that are components of weight loss interventions.