Aortic replacement is the treatment of choice and improves the natural history of dissections involving the ascending aorta. Forty patients (23 male), aged 49.4 years, have been operated at the hospital Clínico de la Universidad Católica. Twenty six presented with acute dissections. Angiography conformed the dissection in 63.3% and computed axial tomography in 84.6% of patients; lately, transesophageal echocardiography has become the most sensitive diagnostic method. Twenty three patients (57.5%) were subjected to emergency operations and 17 to semielective procedures. In 24 patients (60%) ascending aorta was replaced and in 16 a composite graft was used. Operative mortality was 27.5%. Univariate analysis showed that the period in which the operation was performed and the presence of limb ischemia were the only independent predictors of operative mortality. Long term follow up was achieved in 26 patients (89.6%). Actuarial 5 year survival without considering operative mortality was 87.9%. It is concluded that patients with acute dissections involving the ascending aorta should be operated as soon as the imaging diagnosis is complete and, since this is a palliative procedure, a close follow up is required for early detection of complications.