A family history of epileptic seizures including febrile convulsions was found in 15 of 103 patients (15%) with localization related epilepsy with partial seizures with and without secondary generalization, who were operated on because of drug resistance. This rate was significantly higher than that of the cumulative incidence in the general population (4%). The localization of the brain damage did not play a role (temporal lobe resection left: 15%, right: 17%, extra-temporal lesion excision: 20%, hemispherectomy: 11%). Various family members were involved. Some patients had more than one relative with seizures. Thus, 21 relatives suffered from seizures. Eleven of them had generalized tonic-clonic seizures (one grand mal on awakening), 7 had febrile convulsions (4 complicated), and in 1 patient the grand mal seizures on awakening were preceded by absences; 1 had generalized tonic-clonic and complex partial seizures; 1 after complicated febrile seizures likewise had complex partial seizures; another mentally retarded patient suffered from generalized tonic-clonic, axial tonic and myoclonic-astatic seizures. The seizure type of 3 remote relatives was not known. The first seizure occurred in 16 family members during childhood, in 3 in adolescence and in only 1 in adulthood (1 unknown). Eight showed mental retardation of slight degree in most. It is interesting that only one-third of the patients with a family history with seizures were seizure-free after the operation; 5 still had seizures, mostly reduced in frequency, 3 had seizures and isolated auras and 2 had only isolated auras. On comparing the findings in patients with and without a family history with seizures, those with family members with epileptic seizures showed a lower rate of an intellectual deficit (7 vs 47%) and brain tumours (13 vs 44%). Our earlier findings with a different group of patients are thus confirmed: that genetics play a role in symptomatic epilepsies.