The clinical response to lamotrigine has been evaluated in a group of 63 drug resistant epileptic children in an open add-on trial. A negative response was observed in 30 subjects. In 11 patients, after an initial improvement lasting a mean period of 8 months, seizures recurred with the same frequency present before the beginning of the treatment. Twenty-two patients responded to lamotrigine treatment. Period of observation in the responsive group ranged from 1 year to 3 years. Response was complete in 16 patients and in the other 6 a 50% to 90% decrease of seizures was obtained. A complete normalization of the electroencephalogram (EEG) was registered in 10 cases after a mean period of 5 months of therapy. Side effects were mild and limited to 12 patients. Improvement was obtained in social and academic performance. Writing ability improved in one case. Lamotrigine can be considered a useful drug in the therapeutic armamentarium for childhood drug resistant epilepsy.