Seventy six epileptic patients (children and adults) submitted to treatment with RO-5-4023 were studied. RO-5-4023 was administered alone (34 cases) or in association with other antiepileptic drugs. The average dose was 5 mg/day. The cerebrospinal fluid examination was performed in all cases with normal results. In 32 cases the elertoencephalogram was made before and after the treatment. The study allows the authors to draw the following conclusions: 1) the results of therapy were good in 61 cases (81%); 2) the better results were obtained in cases of generalized epilepsy (GM and PM) and in cases of focal non convulsive epilepsy; 3) the results were better when RO-5-4023 was administered in association with other antiepileptics drugs; 4) the electroencephalogram normalized in 46,8% of the 32 cases controled before and after essay; 5) side effects occurred in 32,8% of the cases, consisting of drowsines, ataxia, excitation, fatigue and agressivity; these manifestations disappeared within 10 days after the begining of the treatment.