Hemorrhagic pleural effusions is common in our clinical practice and its usually due to trauma, malignancy and pulmonary embolism. Other rare causes are Bleeding diathesis, Spontaneous hemopneumothorax, Aortic dissection or rupture, Aneurysm rupture or dissection of internal mammary artery, Post-cardiac injury syndrome, Infections like dengue hemorrhagic fever, pulmonary tuberculosis, etc. Aortic dissection is uncommon, a high index of suspicion for acute aortic dissection must be kept in mind when evaluating patients with unexplained chest or back pain. Here by presenting a case of elderly male patient with acute onset right sided chest pain with right haemorrhagic effusion and whose CT thorax revealed aortic dissection. Pleural effusion in aortic dissection is mainly due to inflammation and is a rare presentation. Keywords: Hemorrhagic pleural effusion, Pancreatitis, Cause.