Reports in the literature frequently concern miscellaneous types of dissections. This makes correct interpretation of data difficult. In order to assess the determinants of hospital mortality, the results of 148 consecutive patients over a 23-year period, all operated on for a type A dissection, were reviewed. Mean(s.d.) age was 56(13.1) years, 64% were male. An acute dissection (surgery within 14 days after onset of symptoms) was performed in 139 patients. Stigmata of the Marfan syndrome were present in 6.1% (n = 9). Peripheral vascular ischaemic complications were observed in 27.7%. Nowadays, diagnosis is primarily confirmed using transoesophageal echocardiography (75 correct diagnoses among 76 performed). Operation consisted of repair or replacement of the ascending aorta. Resuspension of the aortic valve was performed in 74 patients, and arch replacement in 25. In 74 patients, distal repair was done under deep hypothermic circulatory arrest. Hospital mortality rate was 23.6% (35 patients), though mortality rate calculated over the period 1990-1993 was 17.4% (P = n.s.). Univariate analysis revealed the following variables to be statistically significant predictors of hospital mortality (P < 0.05): preoperative ischaemic complications, preoperative resuscitation, haemopericardium, postoperative neurological complications, rethoracotomy, renal insufficiency and intestinal ischaemia. Multivariate stepwise logistic regression indicated preoperative resuscitation, postoperative haemodialysis and postoperative neurological complications as the only independent predictors of hospital death. Dissections arising from a primary intimal tear in the descending aorta had a more favourable outcome (P = 0.06, odds ratio 0.1). Although hospital mortality has declined over the past few years, no decline was seen in operative mortality since gelatine-resourcine-formol (GRF) glue is used as a routine. Transoesophageal echocardiography is the first choice in confirming diagnosis. Early operation is advocated, with careful haemostasis, before the development of cardiac tamponade or end-organ ischaemia, as the cornerstone of a successful treatment of a type A dissection. Reduction of neurological complications will further improve the results.