This 9-year-old boy was admitted at the age of 2 with a diagnosis of congenital hemiparesis while the rest of physical and neurological examination was normal. His score in the Wechsler intelligence scale was 80. Right fronto-parietal cortical dysplasia with hemisphere atrophy was evident by computerized tomography scanning and magnetic resonance imaging. The latter, also disclosed abnormal thick cortex which was interpreted as polymicrogyria or pachygyria. Karyotype was normal. He had a hemifacial motor seizure at the age of 7. At the age of 8 frequent atonic or inhibitory seizures were presented. Asymmetric bilateral spike discharges with high voltage in the right hemisphere during the EEG recording were found. His mother, a 35-year-old woman (Full scale; Adult intelligence scale: 85) also had congenital hemiparesis. She never had seizures and her EEG was normal. Magnetic resonance imaging disclosed right fronto-parietal cortical dysplasia with ipsilateral hemisphere atrophy. Karyotype was normal. Our cases should be interpreted as a familial presentation of the anomaly, probably with autosomal-dominant transmission.