Coronary artery ectasia is an uncommon disorder diagnosed in 1 to 4% of patients undergoing coronary arteriography. Coronary artery ectasia is often considered a variant of atherosclerotic coronary artery disease, although other causes should be considered. Complications from this disease usually occur as thrombo-embolic phenomena primarily due to thrombosis in the ectatic segment of the coronary artery. A 53-year old man was transferred to our ER, presenting with acute inferior wall infarction. Coronary angiogram showed a gigantic ectatic right coronary artery (RCA) with occlusion of the mid portion by a huge mural thrombus. We injected and infused glycoprotein IIb-IIIa inhibitor in the RCA, however the lysis of thrombus was minimal. Subsequently, we infused Urokinase into the RCA for 2 days. Follow-up angiography revealed partial lysis of the thrombus. The patient demonstrated no thrombo-embolic events during two months of coumadinization, and follow-up angiography revealed a complete lysis of the thrombus.