Introduction: Picture Exchange Communication System (PECS) is a nonverbal method of communication, used for individuals with Developmental Disabilities to emphasize the need for improved oral hygiene and can also be used for conditioning prior to dental treatment procedures. Aims: To evaluate the effectiveness of PECS on Dental plaque accumulation and oral health of autistic children. Methods: A prospective interventional study was done on autistic spectrum disorder children. Based on PECS, a series of pictures that showed a structured method and technique of tooth brushing were used. These pictures were placed in the bathroom, at home and/or at the autism centre. OHI-S and PI were recorded at each clinical visit (pre and post). Results: Statistically significant change in OHI and PI score was observed. (pvalue< 0.001) Conclusion: PECS can be a useful tool in helping children with autistic spectrum disorder to maintain oral hygiene and also to communicate before and during the preventive dental treatment procedures.