Changes of the clinical pictures and electroencephalographic patterns were studied in 9 patients suffering from epileptic seizures non responsive to common anticonvulsivants, when submitted to daily parenteral administration of diazepam (Valium) and after its interruption. There was decrease of the number and duration of seizures, over to 75%, in 3 patients. These results can be considered as satisfatory, considering the intensity of the seizures. The best results were obtained in those patients which showed predominance of slow waves in the EEGs prior to the begin of the treatment. No side effects were observed during the treatment. Two patients developed tonic seizures coincident with the increasing of fast paroxistic EEG patterns, of localized or diffuse type.