The term Asperger's Syndrome (AS) refers to a clinical picture characterized by social isolation in combination with odd and eccentric behaviour. While the syndrome has been recognized for some time, diagnostic criteria for the disorder have not yet been established or evaluated. The objective of this paper is to describe some of the clinical features of AS. Twenty-eight children and adolescents with AS were compared to a group of psychiatric outpatients (matched on age and sex) who were also socially impaired. The AS subjects showed a range of social impairments essentially different than those seen in the control group. The sex ratio, family history, and presence of neurologic disease in some AS cases, suggest that the etiology of the disorder is similar to that in autism. The methodological limitations of the study are discussed, and a revised set of diagnostic criteria are proposed for AS.