This project is designed to evaluate the acceptability and initial efficacy of a structured group treatment intervention for enhancing social behavior in 40 children with autism spectrum disorders (ASDs). An important long-term goal of this project was to develop a model for delivery of social skills training that could be tested in a larger trial and ultimately exported to schools and community settings. To accomplish these aims, we designed a randomized clinical trial to evaluate a structured social skills program for school age children with pervasive developmental disorders (PDDs)compared to a Wait List control group. Specific aims included gathering preliminary evidence on the efficacy of the intervention on various parent measures of behavior, as well as an assessment of overall social functioning by an independent rater who would be blind to treatment assignment. The Social Skills Development program uses semi-structured activities and peer tutors to promote interpersanal skills. To evaluate acceptability of the program, we planned to track attendance, attrition and parent satisfaction in the trial. Finally, to evaluate the durability of gains achieved during the Social Skills Development program, we re-assessed the subjects initially randomized to the active treatment group at 9 months post-treatment.