Left main coronary artery aneurysms (LMCA) are usually asymptomatic and are rarely encountered during coronary angiography. The most serious complications include coronary thrombosis, acute myocardial infarction and sudden death. Atherosclerosis is the most common cause, although several autoimmune diseases and congenital abnormalities have been associated with the presence of coronary aneurysms. The case of a symptom-free 63-year-old man with a giant LMCA and severely ectatic coronary arteries is presented.