Aortic surgery is a common practice in vascular surgery. In the early sixties of the last century the beggining of the aortic surgery was through retro peritoneal approach, (R.P.A.), later on, the routine procedure used was Transperitoneal (T.P.A.), still however, some vascular surgeons routinely use the retro peritoneal approach. In this randomized prospective study, we have compared aortic surgery in trasperitoneal versus retro peritoneal approach. We have found that the operative time, I.C.U. stay time and postoperative I.V. fluid requirement were statistically significant in favor for R.P.A. Since the peritoneum is not opened and the viscera are not exteriorized in R.P.A., it seems to be more physiologic than in T.P.A.