A 56-year-old man was admitted because of acute myocardial infarction for 10 h of onset. Emergent coronary angiography showed a total occlusion at the middle portion of the right coronary artery. After aspirating thrombus, high-grade stenosis was present in the distal segment. Angioscopy showed only a white thrombus, but not a yellow plaque nor a red thrombus at the initially occluded site. On the other hand, IVUS demonstrated large attenuation indicating a lipid core and cavity obstruction and angioscopy revealed a glittering yellow plaque and red thrombi in the distal segment. Precipitation of thrombus from the distal site to the middle site might have occurred. IVUS and angioscopy might be effective for detecting and evaluating the infarct-related vulnerable plaque and for making the therapeutic strategy when percutaneous coronary interventions are performed.