We report the case of a 76-year-old male patient with a history of coronary artery bypass graft surgery presented with a large pseudoaneurysm emerging from a previously occluded saphenous bypass graft (SVG). A largely contained hematoma is seen in the mediastinum on computed tomography angiography (CTA) of the chest. Flow was seen from the ascending aorta into the pseudoaneurysm through the aorto-ostial opening of the bypass graft. Closure of the aorto-ostial origin of the graft was performed using the AMPLATZER muscular ventricular septal defect (VSD) occluder (St Jude's Medical, St. Paul, MN) with immediate interruption of flow into the graft and the pseudoaneurysm. A repeat CTA of the ascending aorta at 6 months postprocedure continued to confirm an optimal positioning of the occluder with no flow into the pseudoaneurysm. This case offers an endovascular alternative to close the aorto-ostial opening of a saphenous bypass graft in the setting of a rare but potentially life-threatening SVG pseudoaneurysm.