Telescopic aortic arch is a consequence of aortic dissection in Marfan's syndrome, which has not been reported previously. This paper presents the first case of telescopic aortic arch secondary to chronic aortic dissection, as an incidental finding of a forensic autopsy. Here we present a sudden death of a 20 years old male due to cardiac tamponade sourcing from the rupture of ascending aorta. At autopsy, there was a haemopericardium of 800 cc, which comprised blood and clot. The ascending thoracic aorta was dilated and a 1.2 cm ragged linear complete rupture was noticed on the medial side of the front wall of ascending aorta. Examination of aorta showed a second/inner aortic arch just as a tube lying inside the aortic arch. The inner aortic arch was arrised 2.5 cm above aortic valves and lasted at the beginning of the descending aorta. It was 10 cm in length with a lumen 2 cm in diameter and was associated with truncus brachiosephalicus, left common carotid, and left subclavian arteries.