Arteriosclerosis of the small arteries is one of the main causes of microvascular angina, and although some reports have shown favorable prognoses, there is progressive reduction in left ventricular function. The present study evaluated the prognosis of microvascular angina in 86 Japanese patients (51 women, 35 men; average age, 59+/-9 years) who had ischemic ST segment depression, normal coronary angiograms and small artery sclerosis confirmed by endomyocardial biopsies. The mean follow-up period was 7.2+/-3.4 years. Questionnaires regarding their symptoms, cardiac medication, and new events were sent to all patients. Eighty-five patients (98.9%) were still alive at the end of the follow-up period. Chest pain remained in 35.3%; the degree of pain was unchanged in 18.8%, and had lessened in 11.8%. None of the patients died of cardiac events or suffered from a myocardial infarction. At the end of the follow-up period, calcium antagonist was used in 63.5% of patients. Seventeen patients (20.0%) were free of antianginal medication. The prognosis of microvascular angina diagnosed by strict criteria was favorable.