There is some consensus in the literature regarding the cognitive profile of people with Asperger syndrome (AS). Findings to date suggest that a proportion of people with AS have higher verbal than performance IQ, a non-verbal learning disability (NVLD) and impairments in some aspects of executive function (EF). However, there are few published studies on adults with AS and many have compared the AS group to an autistic control group alone. We compared cognitive functioning in 27 AS adults without a history of language delay and 20 normal controls who did not differ significantly in age, gender and IQ. People with AS had significant impairments on a test of visual memory and on EF tasks measuring flexibility and generativity, but not inhibition. There was no significant difference between verbal and performance IQ. Our results suggest that impairments on tests requiring flexibility of thought and generation occur at all ages and across a range of autistic disorders including AS. (Contains 2 tables and 1 figure.)