Language profiles of children with autistic disorder and intellectual disability (n = 36) were significantly different from the comparison groups of children with intellectual disability (n = 26) and typically developing children (n = 34). The group low-functioning children with autistic disorder obtained a higher mean score on expressive than on receptive language, whereas both comparison groups showed the reverse pattern. Nonverbal mental age, joint attention, and symbolic understanding of pictures were analyzed in relation to concurrent receptive and expressive language abilities. In the group with autistic disorder and intellectual disability, symbol understanding and joint attention were most strongly related to language abilities. Nonverbal mental age was the most important predictor of language abilities in the comparison groups. (Contains 4 tables and 1 figure.)