Since 1978, a stroke registry has been carried out in Miyagi Prefecture (2.2 million in population), Japan. Approximately 2,000 cases of stroke were annually registered through 16 hospitals which have cerebrovascular disease units. The incidence of subarachnoid hemorrhage was 17.4 per 100,000 population in 1990. The incidence increased gradually during early 1980's and reached plateau during late 1980's. Further, the trend in the incidence of subarachnoid hemorrhage is compared with those in other communities in other countries as well as Japan.