Thirty-one patients with moyamoya disease, who had been treated for encephaloduroarteriosynangiosis (EDAS), encephalomyosynangiosis (EMS) or EMS with encephaloarteriosynangiosis (EAS) in other hospitals, were admitted to Osaka Neurological Institute from January 1985 to September 1991. Twenty-seven of 57 sides treated by indirect anastomosis showed good filling of the middle cerebral artery (MCA) territory via the anastomosis, whereas 16 and 14 showed fair and poor collaterals via the anastomosis, respectively. Twenty-eight cerebral hemispheres treated by indirect anastomosis underwent further surgery and received superficial temporal artery-MCA anastomosis with or without EMS for still-existent recurrent transient ischemic attacks or completed stroke even after the indirect anastomosis. One patient still had recurrent transient ischemic attacks with quadriparesis after bilateral encephaloduroarteriosynangiosis, which had produced no effective collaterals in the MCA territory; the patient then underwent omental transplantation to the bilateral anterior cerebral artery and MCA territories, resulting in the cessation of the transient ischemic attacks. Clinical improvement after superficial temporal artery-MCA anastomosis with or without EMS was noted in all patients, except on one side, where a completed stroke had resulted in fixed neurological deficits. We do not know the reasons for the uncertainty of the development of collaterals via the indirect anastomosis, but there are many patients who still need direct reconstruction of the indirect anastomosis.