The purpose of the present study was to investigate the effect of pecs training on social skills of children (boys) with autistic disorders. Study procedure was experimental with pretest-posttest design with control group. The statistical population of this research includes all children with autistic disorders in Shiraz in the academic year 2012- 2013. The sample size was 30 boys with autistic disorders that were selected in an available sampling method and assigned into experimental and control group, randomly. So each group consisted of 15 students. Both groups were assessed pre-test. The Experimental group received pecs training in 16 sessions while control group did not. After completion of intervention period for Experimental group the post-test was administered for both groups. The Children's Social Behavior Questionnaire (Jackson, Volkmar & Minderaa, 1998) were administered to assess the social skills. The data analyses by ANCOVA showed that there were significantly increase in the mean scores of social skills and subscales (Not tune, Tendency to withdraw, Orientation problems, Not understanding, Stereotyped behavior, Fear of changes) in experimental group (P<0.01). Findings indicated that pecs training intervention lead to improve social skills of boys with autistic disorders. Therefore, it is suggested to design and implemen pecs training in order to increase children’s social skills with autistic disorders.