In the clinical management of abdominal aortic aneurysm (AAA) patients, it is desirable to determine when, during the course of this disease, the risk of aneurysm rupture justifies surgical intervention and its related complications. Presently, there is no reliable criterion to predict the risk of rupture of AAA and hence make a sound surgical decision. We believe that principles in mechanics may be used to predict the propensity of rupture for AAA. With the development of an aneurysm, the stress on the aortic wall increases progressively (Vorp et al., 1998) until it reaches its gradually decreasing failure strength (Raghavan et al., 1996). Therefore, knowledge of AAA wall stress distribution could be used as a reliable indicator of rupture. Previous stress analyses of AAA by other researchers (e.g., Stringfellow et al., 1987, Elger et al., 1996) were performed using hypothetical, idealized. 2D geometries of AAA and/or simplified mathematical models with the primary goal of understanding the mechanics of the problem. In this work, we demonstrate a methodology to determine more reliable estimates of the in-vivo wall stresses for actual AAA on a patient to patient basis. The ultimate goal of this work is to develop a clinically usable computational tool that may be used for individualized non-invasive assessment of AAA patients.