Childhood obesity is a major health problem with serious long-term health implications. Efforts to determine risk factors beyond genetic predisposition have been equivocal. Common notions of overeating and under-exercising as causes have not been supported by prior research. This combined prevalence and case-control study analyzed a population of children ages 8-10 to ascertain the association between exposure to high-fat foods and low levels of exercise, and obesity. The sample population of Texas school children revealed a 100% greater prevalence of childhood obesity relative to national normative standards established from 1976-1980. Neither high-fat food intake nor reported level of physical activity were independent risk factors for this condition. However, they may exert a synergistic effect when both are present in the same child. Development of more sophisticated population-based instruments will enable larger studies to investigate risk factors for childhood obesity.