Introduction: Considering high prevalence of childhood obesity and importance of its prevention and control, and the role of mother's perceptions of their children behaviors, this research was aimed to study the impact of health education through health belief model (HBM) about prevention and control childhood obesity on the mothers, perceptions of overweight school children in 17th district, Tehran City, 2007-2008.

Methods: In this quasi-experimental study we selected100 students with BMI more than standard for their age and sex from 5 schools thorough a cluster random sampling method at 17th district, Tehran City. They divided randomly in two groups: experimental & control. We used questionnaires including 40 questions in seven demographic sections about HBM dimensions(sensibility, severity, perceived profits, perceived obstacles, self-efficacy, and action-guide) completed by children mothers. Then mothers randomly divided in two groups (Experiment and control).Experiment group gives education. For presenting the educational materials we used different educational method such as lectures, questions and graphs. For two sessions of 30 minutes period mothers education completed. Control group had no education. Two weeks later, mothers again completed the questionnaires. The data were analyzed by the spss15 for windows, for analysis of covariance (ANCOVA) and Pearson correlation tests. Results:Eleven per cent of mothers failed to perceive their overweighed child as overweight, and 83/3% of mothers after education, accepted that their children are overweight these were mothers who failed to perceive their overweight child as overweight before education. The results of analysis of cov- ariance (ANCOVA) were significant between means of two group's mothers attitudes, and proved a significant difference between two mean in elements of HBM (p<0/0001). Demographic factors showed no significant difference between two groups.

Conclusion: Education of prevention and control of childhood obesity by means of health belief model can promote mothers perceptions, and can affect on the positive maternal attitude.