Type III endoleak is one of the causes of secondary intervention after endovascular aortic aneurysm repair (EVAR). We report two cases of a late type III endoleak with a review of the literature. One case had a disconnected iliac limb and the other case was due to a defect of the main body fabric at the bifurcation level. Both cases were successfully treated by open conversion. Before open conversion, it should be determined how to get proximal aortic control (suprarenal vs. infrarenal and cross-clamping vs. balloon inflation). When the suprarenal aortic control is required, to reduce suprarenal clamping time, it is not necessary to remove the endograft completely. Partial endograft removal and a graft-to-graft anastomosis is an alternative, if it is well incorporated and not infected. Making a plan for delayed open conversion should be individualized according to the type and status of the endograft and the vascular anatomy.