We, Research Committee on Moyamoya Disease sponsored by Ministry of Health, Labor, and Welfare, Japan, have revised the diagnostic criteria for moyamoya disease for the first time in seven years in response to recent changes in the disease concept and diagnostic methods. We have recently reported on the background and contents of the revision in “Surgery for Cerebral Stroke,” the official journal of the Japanese Society for Surgery on Cerebral Stroke in Japanese. We will soon publish an English version to share it with physicians and researchers around the world.