Abdominal Aortic Aneurysms (AAAs) are a major cause of death in Western societies. However, the factors responsible for the growth and ultimate rupture of AAA are not fully understood. Using computation fluid dynamics combined with CT images, the flow patterns and wall shear stress (WSS) in the AAA of a patient were studied. AAA geometry was obtained from images acquired during a routine CT scan, and a realistic abdominal aortic flow waveform was used as an upstream boundary condition. The computational results showed the presence of multiple flow recirculation zones and overall low WSS in the bulge of the aneurysm. This may provide some insight into the growth of thrombus in AAA.