To examine whether prevalences of asymptomatic ischemic heart diseases in type II diabetic patients are correlated with the degree of diabetic nephropathy, 201TI scintigraphies with dipyridamole loading were performed in 28 type II diabetic patients without any chest discomforts. Positive findings of ischemic changes were found in 5 (28%) of 18 patients with normoalbuminuria (urinary albumin excretion rate, AER less than 20 micrograms/min) and 5 (50%) of 10 patients with micro- or macroalbuminuria (AER greater than 20 micrograms/min). Coronary angiography (CAG) was performed in 6 of 10 patients with positive findings of 201TI scintigraphy. No stenotic findings were found in any patients, but wall motion was decreased in some patients and pulmonary artery pressure was increased in one patient. As stenosis of arteries with diameter of more than 0.3 mm can be detected by CAG, it seems likely that microangiopathy may play some role in the pathogenesis of asymptomatic ischemic heart disease detected with 201TI scintigraphy.