SPECT of regional cerebral blood flow was performed using Tc-99m-HMPAO in 28 patients with cerebrovascular disease and quantitative analysis was done. Cerebral asymmetry index and percent index of asymmetry of cerebellar hemisphere of patients with cerebral infarction or ischemia were 0.764¡¾0.576 and -5.6¡¾7.1% and those of intracranial hemorrhage was 0.416¡¾0.251 and -2.5¡¾4.1% respectively. According to PIA of cerebellar hemisphere, 12 patients showed crossed cerebellar diaschisis. Tc-99m-HMPAO SPECT seemed to be a useful tool for the evaluation of regional cerebral blood flow.