The aim of the present study was to investigate-the effect of corpus callosotomy on seizures, with emphasis on the psychosocial outcome. Data were retrospectively obtained from 20 patients (mean age 20.8 years, range 6-46). Sixteen of the operated patients took part in the 39-month (range 19-62) follow-up. Outcome measures were post-operative seizures, changes in the antiepileptic drug treatment, surgical complications including disconnection syndrome, degree of dependency according to the Barthel index, quality of life, burden on caretakers and satisfaction with the treatment. Half of the patients had a favorable seizure outcome, and of these 50% noticed an improved quality of life and were satisfied with the treatment. Four patients suffered from symptoms of cerebral disconnection syndrome which interfered with the activities of daily life. One patient died of complications 3 months after the operation. There were no significant changes in antiepileptic drug treatment, the patients' social lives or the burden of the patients on the caretakers. The conclusion is that prospective studies are needed to clarify the criteria for optimal patient selection to increase the likelihood of a positive psychosocial outcome.