Postural control was evaluated in samples of autistic, normal, and mentally retarded children in this pilot study using a recently developed, computerized posturographic procedure. A battery of postural positions was administered including postures involving some degree of "stress" (e.g., occluded vision or standing on pads). The postural patterns of children with autism differed from those observed in normal children, in mentally retarded children, and in adults with vestibular disorders. In comparison to normal children the autistic subjects were less likely to exhibit age-related changes in postural performance and postures were more variable and less stable with more lateral sway. Autistic subjects also exhibited a "paradoxical" response of greater stability with more "stressful" postures, putting excessive weight on one foot, one toe, or one heel. The implications for neuroanatomical models of autism are discussed.