Acute aortic dissection is initiated by an intimal tear most often found in the ascending or descending thoracic aorta. A high index of suspicion is necessary to establish diagnosis. In the acute setting, transoesophageal echocardiography is very helpful to confirm the diagnosis, locate the intimal tear and demonstrate the extent of dissection. Acute type A dissection is a surgical emergency contrary to type B dissection which is treated medically unless complications arise. With correct treatment, mortality of these life-threatening disorders has been reduced during the last decade and long-term survival of discharged patients is around 50%. Careful follow-up is necessary to detect late complications, mainly the occurrence of a post-dissection aneurysm.