The objective of the present study was to determine the risk factors for operative and short-term mortality, and morbidity after a Bentall operation, Between July 1994 and February 2001, 86 consecutive patients (70 males) Underwent a modified Bentall operation at our hospital. The aortic pathology was acute aortic dissection in 12 (14%), chronic dissection in 9 (10.5%) and degenerative aneurysm in 65 (75.6%). Mean age was 48 +/- 15 years. Eleven preoperative, 8 intraoperative and 6 postoperative variables of these patients were retrospectively analyzed using univariate and multivariate logistic regression analysis. Six patients died in the hospital (6.9%) and 2 died within four months after being discharged from the hospital. Mean follow-up time was 33 23 months (2 months to 8 years). The survival rate among hospital survivors was 88% at 3 years and 77% at 6 years. Univariate predictors of in-hospital and short-term mortality were the presence of aortic valve calcification, stenotic aortic valves, renal failure, and cardiac failure after the operation. Multivariate analysis revealed no independent risk factors. Risk factors for morbidity were etiology of acute dissection, use of circulatory at-rest, transfusion of blood and fresh frozen plasma more than 2 units each, cross clamp and cardiopulmonary bypass times (exceeding 90 and 140 minutes, respectively), and performing concomitant procedures.