In recent years, there has been a resurgence of interest in the retroperitoneal approach to the aorta; however, there has been only few prospective studies in the literature and the results are controversial. For this reason, we assessed peri- and postoperative problems associated with both procedures and compared the results of each one in a prospective study. Between 1989 and 1990, 163 patients underwent operative procedure because of an aortic or aorto-iliac lesion. 121 were operated on through the "classical" transperitoneal method (87 had aortic aneurysm, 34 aorto-iliac occlusive disease) whereas in 42 patients, retroperitoneal approach of the aorto-iliac bifurcation was performed (28 because of aortic aneurysm and 14 because of occlusive disease). Early mortality was 0 in the group with retroperitoneal approach, despite the fact that 66% of these patients were classified as high-risk patients (American Society of Anesthesia risk classification III or IV); it was 0.8% in the group with classical approach. Retroperitoneal group demonstrated significant decrease in blood (630 vs 1300 ml) and crystalloids (1700 vs 3250 ml) requirement, shorter nasogastric intubation time (1.6 vs 4.4 d) and quicker peroral intake. Significant pulmonary and cardiac complications were less often observed in the group of patients after retroperitoneal approach to the abdominal aorta. Mean postoperative hospital stay was significant shorter when compared with the transperitoneal group (8.5 vs 13.9 d). Our results confirm that retroperitoneal approach is an excellent alternative to the transperitoneal method for elective reconstructive surgery of the abdominal aorta. It is associated with better tolerated incisional pain, decrease in cardiac and pulmonary complications and thereby decreased hospitalization time.(ABSTRACT TRUNCATED AT 250 WORDS)