Introduction & Objective: According to significance of pervasive developmental disorders (PDD) in children and the increasing rate of its prevalence in referred patients to clinic in recent years and due to absence of any report about the rate of PPD in our country, this study was carried out. The aim of this study was to determine the prevalence of PPD in a sample of Iranian children who referred to medical and rehabilitation centers.

Materials & Methods: 248 children who referred to three medical-rehabilitation centers were participated in the research. Accessible sampling with diagnosis of PDD based on DSM-IV criteria was chosen. The obtained data were analyzed using descriptive statistics methods such as percent and frequency distribution.  

Results: Autistics disorder was most prevalent among pervasive developmental disorders. In this research Autistic disorder (proportion 4/1 to 1), Asperger disorder (proportion 3 to 1) and childhood disintegrative disease were more prevalent in boys than girls. Ret disorders was observed only in girls and pervasive developmental disease (NOS) was seen in both sexes.  

Conclusion: The results showed that pervasive developmental disorders are 4 times more prevalent in boys than girls and the findings of this research were consistent with those of previous studies.