Cardiovascular malformations, especially coarctation of the aorta and bicuspid aortic valve, are common in patients with Turner's syndrome. Only 46 patients with aortic dissection and/or rupture have been described. All patients had associated aortic dilation or aneurysm. In all cases except three, involvement of the ascending aorta was present, making surgery often imperative. We describe a rare case of a DeBakey type IIIb aortic dissection (without involvement of the proximal aorta) in a patient with Turner's syndrome mosaicism. The dissection occurred two weeks after a caesarean section because of eclampsia. No aortic dilation or other cardiovascular malformations were found. The distal extension and uncomplicated nature of the dissection indicated medical management. After fifteen months of follow-up, she is clinically doing well and repeated CT scan shows a stable dissection of the descending and abdominal aorta without dilation.