Changes in the mean cerebral blood flow (mCBF) with growth in normal children (1-20 years old) were evaluated, and compared to serial mCBF changes in children with spontaneous occlusion of the circle of Willis (moyamoya disease) after vascular reconstructive surgery. mCBF gradually decreased with growth in control children. Preoperative mCBF was similar or decreased in moyamoya disease patients with transient ischemic attack, and slightly decreased in those with cerebral infarction. Postoperative mCBF gradually decreased similarly to physiological changes with growth in controls. These results suggest that changes with age should be considered when preoperative and long-term cerebral hemodynamics are evaluated in children with moyamoya disease.