Neuronal migration disorder is a rare group of congenital malfomations of the brain caused by insults to migrating neuroblasts during the six to fifteen gestational weeks. We identified 36 neuronal migration disorders on CTs in two patients and on MRIs in 34 patients and analyzed their characteristic radiologic, clinical, and EEG findings. These 36 patients with neuronal migration disorders consisted of 18 with schizencephaly, eight with pachygyria, five with heterotopias, three with lissencephaly, and two with polymicrogyria. Patient ranged in age from 6 months to 37 years old and mean age was 18.2 years old. Associated cerebral anomalies included ventricular dilatation in 13 patients, agenesis of septum pallucidum and hypoplasia of corpus callosum in nine patients. Lissencephaly was associated with other cerebral anomalies most frequently and all of them had ventricular dilatation and hypoplasia of corpus callosum. Only one patient with pachygyria had ventricular dilatation. Clinically, these patients presented with seizures in 91.7%, speech impairment in 33.3%, abnormal motor function in 30.5%, developmental delay in 27.8%, mental retardation in 25%. Patients with large or medium size of neuronal migration disorders had significantly more severe developmental delay(p=0.001), mental retardation (p=0.004) and speech impairment (p=0.01) than those with small size. Abnormal motor dysfunctions were not significantly associated with lesion size statistically. Seizures did not correlate with lesion size.