Migrating focal seizures in infancy are an unusual and often overlooked epilepsy syndrome, with onset before age 6 months, in which nearly continuous seizures involve multiple, independent areas of both hemispheres with an arrest of psychomotor development. We describe a patient with migrating focal seizures in infancy whose seizures began at age 45 days. The seizures were refractory to common antiepileptic drugs. At age 6 months, the infant received potassium bromide and became almost seizure-free. The infant developed severe neurologic impairment, with marked axial hypotonia and an absence of visual contact and head control. At age 8 months, the child suddenly died. Pathologic findings included multiple malformations of cortical development, polymicrogyria, and focal cortical dysplasia associated with hippocampal sclerosis.