Forty one children (20 boys, 21 girls) aged 6-10.8 years (mean age 8.6 years) who were affected with idiopathic epilepsy underwent neuropsychological (Wechsler Intelligence Scale for Children, Bender test) and behavioural assessment (Personality Inventory for Children; this was also used in a matched control group). Further information was obtained by teachers' reports. School underachievement occurred in 25 children (61%). Statistical analysis showed no influence of sex, social background, age of onset, seizure type, duration of illness, features seen on electroencephalography, and treatment. School failure was due to poor performance in almost all academic fields, and was associated with higher visuomotor impairment; children showing good school performance had a higher mean IQ and less visuomotor impairment. The behaviour of children with epilepsy who had a good academic performance did not differ from that of their healthy peers. Emotional maladjustment (social skill impairment, depression, poor motivation, and low self esteem) was associated with poor school performance. Such problems, that may complicate the course of idiopathic epilepsy and require an appropriate educational programme, should be carefully considered by the clinician.