Persons with epilepsy are at increased risk of cognitive deficits as a result of various factors like etiology, structural brain lesions, seizure frequency, seizure type, age at onset of epilepsy, hereditary factors, psychosocial factors, and possible adverse effects of antiepileptic drugs (AEDs). Despite the fact that the majority of epilepsy patients are seizure-free, previous studies on the relationship between epilepsy-related variables and cognitive function have mainly been conducted on patients with persisting seizures. In this study 158 adults with epilepsy on AED monotherapy and without epileptic seizures for at least 2 years were investigated with a neuropsychological test battery in addition to a neurological examination, MRI and EEG. The major findings were that the group had education and employment status similar to the population mean and neuropsychological function in the normal range. In the patient group without idiopathic generalized epilepsy known cerebral etiology was found to be a highly significant predictor of neuropsychological deficit. For patients with idiopathic generalized epilepsy, early seizure debut at < or =18 years was a powerful predictor of neuropsychological impairment.