In the last few years, advances in surgical techniques and in organ protection adjuncts have improved outcomes in thoracic (TAA) and thoracoabdominal aortic aneurysm (TAAA) surgical repair, although mortality and morbidity are still noteworthy. The aim of the current retrospective study is to determine whether the use of adjuncts influenced mortality and morbidity rates. From 1993 to 2003 we performed 353 procedures for TAA (175 cases) and TAAA (178 cases). This series has been divided into two consecutive groups: in group I (from 1993 to 1997), distal aortic perfusion with left atriofemoral bypass and cerebrospinal fluid drainage were used selectively, and in group II (from 1998 to 2003), the adjuncts were used routinely (together with surgical techniques of less invasive approach in selected cases). Total in-hospital mortality rates were significantly different ( p < 0.05): 15.9% in group I and 8.6% in group II. The overall incidence of paraplegia or paraparesis in group I was 8.3% and in Group II it was 5.1%. Renal failure occurred in 9.6% of group I and in 4.1% of group II. The incidence of respiratory failure in group I was 28%, and was 17.9% in group II. Respiratory failure was significantly lower ( p < 0.05) in group II. The reduction in the incidence of renal failure and paraplegia in the two groups was nonsignificant. In conclusion, the use of adjuncts and our improved experience allowed us to achieve a significant improvement in mortality and major morbidity rates in the group of patients operated on after 1998.