At the present time there are a large number of adults who have suspected Asperger syndrome (AS). In this paper we describe a new instrument, the Adult Asperger Assessment (AAA), developed in our clinic for adults with AS. The need for a new instrument relevant to the diagnosis of AS in adulthood arises because existing instruments are designed for use with children. Properties of the AAA include (1) being electronic, data-based, and computer-scorable; (2) linking with two screening instruments [the Autism Spectrum Quotient (AQ) and the Empathy Quotient (EQ)]; and (3) employing a more stringent set of diagnostic criteria than DSM-IV, in order to avoid false positives. The AAA is described, and its use with a series of n�=�42 clinic-patients is reported. Thirty-seven of these (88%) met DSM-IV criteria, but only 34 of these (80%) met AAA criteria. The AAA is therefore more conservative than DSM-IV.