Kawasaki disease is an acute systematic angiitis, specifically affecting the coronary arteries in young children. Coronary aneurysms develop in 10 to 15% of patients with Kawasaki disease. The coronary aneurysm frequently changes into coronary stenosis and obstruction. Hitherto, we could observe and access the severity of these coronary lesions with the use of two dimensional echocardiography and selective coronary angiography. Angiography is the most sensitive means available for diagnosing significant coronary lesions and their severity. However, it is insensitive for detecting intraluminal minute and pathologic changes such as intimal thickening, regeneration of endothelium and thrombus. Recent advance in fiberscopie technology, enabled us to observe the inside of coronary artery percutaneously. We tried to use this angioscopic technique for the observation of coronary lesions in eight patients with Kawasaki disease at chronic stage.