PURPOSE: The Picture Exchange Communication System (PECS) is a popular communication-training program for young children with autism spectrum disorders (ASD). This meta-analysis reviews the current empirical evidence for PECS in affecting communication and speech outcomes for children with ASD. METHOD: A systematic review of the literature on PECS written between 1994 and June 2009 was conducted. Quality of scientific rigor was assessed and used as an inclusion criterion in computation of effect sizes. Effect sizes were aggregated separately for single-subject and group studies for communication and speech outcomes. RESULTS: Eight single-subject experiments (18 participants) and 3 group studies (95 PECS participants, 65 in other intervention/control) were included. Results indicated that PECS is a promising but not yet established evidence-based intervention for facilitating communication in children with ASD ages 1-11 years. Small to moderate gains in communication were demonstrated following training. Gains in speech were small to negative. CONCLUSIONS: This meta-analysis synthesizes gains in communication and relative lack of gains made in speech across the PECS literature for children with ASD. Concerns about maintenance and generalization are identified. Emerging evidence of potential preintervention child characteristics is discussed. Phase IV was identified as a possibly influential program characteristic for speech outcomes.