We have reported the characteristic dynamic changes at the base of the brain in childhood Moyamoya disease in terms of follow-up angiography. So we have classified the angiographical findings of Moyamoya disease into six stages. However, there have been no report that proved these findings in long-term follow-up. On the other hand, these angiographical findings are mainly observed in children, we can seldom to find out any changes in adults. We performed long-term follow up angiography in adult cases whose onset was in childhood to clarify the natural course of this disease and to understand the difference between the cases of children and adults. Eleven cases (4 males and 7 females) of Moyamoya disease were investigated by angiography. Average onset was 5.1 years old. All of them were diagnosed by initial angiography in childhood (average age were 6.5 years old) and they grew up into adolescence (average age were 18.6 years old) at the time of follow-up study. Initial symptoms of them were all ischemic (TIA 7, RIND 2 or completed stroke 2). The symptoms at the time of follow-up were mental retardation in 5 patients, slight neurological deficits in 1, TIA in 2 and normal in 3. Among them, one patient had suffered from intraventricular hemorrhage. The results were as follows: the progression of angiographical stages was observed in 95% of sides. In 71% of sides, angiographical stage was in 5 or 6 which is thought to be an end stage of this disease.(ABSTRACT TRUNCATED AT 250 WORDS)