To evaluate the diagnostic accuracy of detection of angina-related coronary arteries in patients with unstable angina pectoris. Twenty patients with unstable angina pectoris underwent 123I-BMIPP scintigraphy at rest. A mean duration from last anginal attack to 123I-BMIPP scintigraphy was 408 +/- 3.2 days. Seventeen of 20 angina-related coronary territories were detected by reduced 123I-BMIPP uptake. The sensitivity and specificity for detection of angina-related coronary arteries were 85% and 95%, respectively. The decrease in myocardial uptake of 123I-BMIPP agreed with the decrease in regional wall motion by using ultrasonic echocardiography. 123I-BMIPP scintigraphy may be useful for detection of angina-related coronary artery in a routine clinical examination in patients with unstable angina pectoris.