Dissecting hematoma is a rare cause of acute closure after PCI. Because angiographic findings of dissecting hematoma are various from insignificant to total occlusion, IVUS is necessary for the accurate diagnosis. If dissecting hematoma was managed as a thrombotic occlusion, a catastrophic result may occur. We report a successful case of a rapidly propagating dissecting hematoma with a prompt acqusition of IVUS image and consecutive multiple stenting. A 62-year-old woman was admitted to our hospital for unstable angina. Her risk factors for CAD were hypertension and hypercholesterolemia. There was no significant finding on ECG, cardiac markers and echocardiography. Angiography revealed significant stenosis of proximal LCX. We started one-stage PCI with a Runthrough guide wire and a 6 Fr. Judkins Lt. guiding catheter. Just after preballooning with Maverick 3.5-8 mm(10 atm), she complained of severe chest pain but her blood pressure maintained. Angiography showed dissection at the target lesion and slow distal flow. And then we performed IVUS which showed blood flow through dissection into media and formation of huge hematoma along distal segment. Subsequent angiography showed new stenosis of distal LCX. We put two stents from proximal to distal LCX. Follow angiography showed a second stenosis of far distal LCX which means distal propagation of dissecting hematoma. A third stent(Element 3.0-28) was placed. Final angiography showed no residual stenosis with good distal flow. The chest pain was nearly resolved.