Autistic symptoms appear to change during adolescence. This study replicates an earlier one (McCallon, 1985) which attempted to validate the use of the Childhood Autism Rating Scale (CARS) with adolescents. The standard observation method of administration was used. Additionally, information obtained in structured parent interviews was used to score a CARS. Subjects were nine autistic and nine nonautistic retarded adolescents from 13 to 21 years of age. Results suggested that the CARS, administered either way, validity discriminates between retarded adolescents who are diagnosed as autistic and those with other handicaps. Methodological limitations of the present study are discussed.