Marfan syndrome is an autosomal dominant genetic disorder of the connective tissue. The most serious complications of this syndrome are defects of the heart valves and aorta. Aneurysms of thoracic aorta are known to develop in Marfan syndrome. Other causes for development of aneurysms of the thoracic aorta are trauma, infections, valve and arch anomalies, genetic disorders, and atherosclerosis. These aneurysms upon rupture may lead to sudden deaths. They are usually detected during routine screening or follow-up of such persons suffering from Marfan syndrome and upon death will be certified by the treating physician. Thus, an autopsy surgeon rarely comes across such deaths. One such case of sudden death due to cardiac tamponade consequent upon rupture of dissecting aortic aneurysm in a 33-year-old male who complained of throbbing pains in the chest, radiating to back, became breathless, cyanotic and died on the way to hospital is being presented here.