Sturge-Weber syndrome was diagnosed in a neonate on basis of a characteristic port-wine stain. In the absence of any acute neurologic episode, MR images obtained when the infant was aged 3 months showed a typical pial vascular dysplasia, as well as prominent hypotrophy of the homolateral hemisphere. Areas suggesting the presence of developmental dysplasia of the cerebral mantel were found in association with the typical pial vascular anomaly. The prenatal effect of Sturge-Weber disease on normal brain development may best be explored by using a better evaluation with cerebral imaging shortly after birth.