The case histories are presented of three 17 year old identical male triplets with Asperger's syndrome. They show the impairments affecting social interaction, non-verbal communication and imagination, the motor clumsiness, and the circumscribed interests characteristic of that condition. They also have some features in their history and present behaviour more typical of childhood autism. Despite marked overall similarities, the three differ in the severity with which their problems are manifested. A relationship can be found between the amount of peri- and post-natal trauma, degree of intellectual impairment and number of autistic features. The findings support the hypothesis that autism and Asperger's syndrome are on the same continuum of pathology.