Objective: This study investigates the prevalence of behavioral disorder among preschool children of Razan city. Method: The research method was descriptive-epidemiology. 327 preschool children (144 girls and 183 boys) were selected by random cluster sampling from governmental and private elementary schools. Information were collected by Child Behavior Checklist (CBCL), Caregiver-Teacher Report Form (C-TRF) and questionnaire that made by researcher. Data were analysis by descriptive statistics, Chi square and Pearson correlation coefficient. Results: Analysis revealed that 9/8 % of preschool children had behavioral disorder and the prevalence of behavioral disorders includes anxiety, physical, withdrawal, attention, internalized and externalized disorders in boys were more than girls. Furthermore, the prevalence of behavioral disorders in rural areas was more than urban areas. Conclusion: The relatively high percent of behavioral disorders in preschool children emphasize the necessity of educational planning and implementing for parents and teachers, also present psychological and counseling services.