BACKGROUND: The syndrome of malignant migrating partial seizures in infancy is a rare epileptic syndrome with a devastating course characterized by early onset of continuous pharmacoresistent multifocal seizures arising from multiple independent sites of both hemispheres with unknown etiology. PATIENT: A 2-month-old boy with the characteristic clinical and electroencephalograph pattern of migrating partial seizures in infancy was treated with potassium bromide. His seizures were unresponsive to the conventional and new generation antiepileptic drugs. RESULTS: The seizure frequency was reduced markedly with potassium bromide. CONCLUSIONS: Potassium bromide, an old antiepileptic drug, is useful in the treatment of malignant migrating partial seizures in infancy.