BACKGROUND: Although childhood obesity is an increasing public health problem in our society and a number of regimens have been developed and distributed for the treatment of adult obesity, few studies have focused on therapeutic programs for obese children. The objective of this study was to deveIop and measure the effects of an OPD-based childhood obesity control program. METHOD: 'The OPD-based childhood obesity control program was developed by reviewing the preexisting literature and consulting specialists. It was applied to the 4-6th grade obese(obesity index >or=30% ) children. The effects of intervention were assessed by the changes in obesity-related behavior, caloric and nutrient intake and exercise amount. The effects in the OPD-based group (group I) were also compared with the school-based group (group II) and the no intervention group (group III). RESULTS: The OPD-based program was developed based on behavioral modification principles such as self monitoring, stimulus control, positive reinforcement, social support, cognitive change and behavioral contracts and contained diet and exercise therapy. The developed program was applied to 34 pairs(child and mother) in the treatment group of which 21 pairs completed the basic session and 17 pairs completed the additional follow up session. Significant changes, decreases, in obesity index were observed In the OPD-based group. No significant changes were found in the school-based group whereas increased degrees of obesity were found in the no intervention group. Obesity related behavior scores were significantly increased in both the OPD- and school-based groups. The children in both the OPD-based group showed significant decrease in dietary intake and increase in exercise amount. CONCLUSION: Although it was a short-term treatment result, the OPD-based program was more effective than the school-based program in childhood obesity control. We suggest that a control program of comparable intensity and individualization as ours is required, for effective childhood obesity control.