Abstract INTRODUCTION: Childhood obesity is a cultural and medical problem and is usually a refractory to treatment. The objective of this study was to assess the effects of parental therapy behavior and relaxation methods on children in controlling childhood obesity. methods: In this randomized controlled clinical trial, 90 obese children aged 10-17 years were randomly divided into three groups of equal number. All three groups received similar diet and exercise recommendations. The first group of children attended 15 relaxation sessions. Parents of the second group participated in 15 behavior therapy sessions. The third group was considered as control. Data were analyzed by SPSS 13. Mean changes of weight, BMI and WC were calculated. results: Mean BMI decreased in all three groups after the intervention. This decrease was more remarkable, but not significant in the first group. Mean weight decreased in the first group but increased in the second group. Mean WC decreased in all three groups. This decrease was more obvious, but not significant in the first group. CONCLUSIONS: Stress leads to sympathetic system arousal which it associated with many pathologic conditions. Elicitation of relaxation response can help individuals embrace healthy lifestyle choices. Relaxation and parent behavior therapy can be considered as useful methods of controlling childhood obesity. Keywords: Obesity, children and adolescents, relaxation, behavior therapy, parents.