Moyamoya disease is characterized by progressive stenosis of the distal portion of the internal carotid arteries and fragile collateral vessels in the brain. The precise pathogenesis is still not known. Although extracranial vessel involvement is very rare, coronary arterial involvement has recently been reported. Here, we report a case of diffuse, multivessel coronary spasm leading to cardiac arrest and myocardial infarction in a 47-year-old man with moyamoya disease with no underlying emotional or physical stress.