Psychogenic pseudoseizures typically are thought to reflect emotional disturbances. Studies have suggested that patients with psychogenic pseudoseizures may also have impaired neuropsychological function. We examined intellectual and neuropsychological performance in a large sample of patients with well-documented psychogenic pseudoseizures. Patients with pseudoseizures only (Pure group) and patients with both pseudoseizures and epilepsy (Mixed group) were included. For the total sample, the WAIS-R IQ scores were quite variable. Full Scale and Performance IQ ranged from deficient to very superior. The Full Scale IQ was in the low average or borderline range in 41.5% of patients. A striking finding was the high incidence of impaired performance on the Halstead-Reitan Neuropsychological Battery in both the Pure and Mixed groups. Considering the neuropsychological variables for which published cut-off scores are available, more than 50% of the total sample (as well as the Pure and Mixed groups) scored in the impaired range on more than half the measures. The Halstead Impairment Index, which reflects the overall level of neuropsychological performance, was in the impaired range (0.5-1.0) in 63% of the sample. Given the high incidence of accidents and physical trauma reported by our patients, we postulate that head trauma might be responsible for neuropsychological impairment in an appreciable number of the patients in this sample.