Objective: Pervasive developmental disorders are a group of developmental conditions originating in childhood that involve some delay or impairment in communication and social skills, behaviors, and cognitive skills. This review article will give an overview over the controversial role of omega3 supplementation on the behavioral patterns particularly in improving sleep patterns and hyperactivity in children with autism spectrum disorders. Methods: This paper will describe the important role of the omega-3 fatty acids in the structure and function of the brain, the beneficial effects of omega-3 on hyperactivity and sleep as well as other behavioral patterns, and will introduce the potential food sources of omega 3. Conclusion: Recent studies confirmed that autistic children have lower levels of omega-3 in their blood than do normal children. Treatment of hyperactivity in autistic children with more severe signs using omega-3 appears most promising and it was approved by biochemical tests. In addition, in some studies the potential effects of omega-3 fatty acids in decreasing the aggressive and impulsive behaviors in autistic children has been observed, but the mechanisms by which the omega 3 perform these effects are not fully understood.