Teaching children with autism is a challenging task for educators and parents, as the children display marked deficits in language and social behaviors. One of the major goals of an intervention program for children with autism is to provide them a method of functional communication and ample opportunities to practice these skills. For some children with autism, a communication system that uses alternative and augmentative forms of expression may be necessary. Children with autism (N = 8) between the ages of 9 and 12 years were selected from special schools in Mumbai for this experimental research. The study aimed to determine the effectiveness of Makaton Vocabulary Language Program, a system of alternative and augmentative communication (AAC), on development of language and social behavior of children with autism. The subjects received 12 sessions of language intervention using AAC. language assessment tool for autistic children (LATCA) and social behavior rating scale (SBRS) were used as instruments for measurement. While the researcher administered LATCA, the classroom teachers used the SBRS as a checklist for social behavior. The comparison of their pre and post test mean scores showed a significant change in language and social behavior. Use of AAC had a positive effect on development of receptive and expressive language. AAC usage was also found effective in enhancing social behavior of children with autism. (Contains 4 tables.)