We encountered two fusiform abdominal aortic aneurysm cases with delayed AFX endograft (Endologix Inc) migration >4 years after placement. These cases showed shortening and slight angulation of the main body in the anteroposterior direction. We speculate that the potential mechanism relates to the AFX portion that is easily shortened at the bifurcation of its stent structure. This portion might contribute to delayed migration after slight angulation of the main body. Preoperative three-dimensional computed tomography should be performed from the anteroposterior and lateral views. Although the AFX is useful for narrow bifurcations, one should consider the patient's anatomy before deciding to use an AFX endograft.