OBJECTIVE To analyze indocyanine green angiography (ICGA) features in one case of diffuse choroidal hemangioma associated with Sturge-Weber syndrome. METHODS Color fundus photography, fluorescein angiography (FA) and ICGA were performed in a patient with diffuse choroidal hemangioma associated with Sturge-Weber syndrome. RESULTS The diffuse choroidal hemangioma was not identified by FA. ICGA revealed that the vascular tissue of the diffuse hemangioma filled rapidly with dye during the arterial phase of the choroidal angiogram; copious dye leakage appeared early and persisted into the late phase of angiography. Late "wash-out" phenomenon was not observed 30 minutes after dye injection. Sectors of reduced choroidal perfusion in the upper or lower half of the midperiphery were present. CONCLUSIONS ICGA may be an important and sensitive technique in detecting the diffuse choroidal hemangioma associated with Sturge-Weber syndrome.