Moyamoya is an obstructive cerebrovascular disease characterized by a cerebral angiographic picture of stenosis or occlusion of main cerebral arteries with an abnormal vascular network at the base of the brain. No definitive cause has been found for this disease and opinion is still divided between a congenital and an acquired etiology. Hemiplegia of sudden onset and epileptic seizures are the prevailing presentation in childhood, while subarachnoid bleeding occurs more frequently in adults. We report a new case of childhood moyamoya with clinical onset of the neurological symptoms within the 3rd year of life; during the child's illness the maternal grandmother presented with moyamoya disease too. Antiaggregating and calcium-antagonist drugs seem effective in preventing further vascular accidents, while a surgical approach is not possible. Computed tomography, single positron emission computed tomography, and magnetic resonance imaging are very useful in the diagnosis of this rare disease.