A celiomesenteric trunk (CMT) accounts for fewer than 1% of all visceral artery anomalies. Aneurysms involving a CMT are exceptionally rare: our search of the literature found only eight cases reported. We treated a 73-year-old man with both a fusiform CMT aneurysm and an abdominal aortic aneurysm (AAA). The celiac artery and superior mesenteric artery were reconstructed by performing a retrograde prosthetic-graft bypass originating from the right limb of the bifurcated aortic graft used to repair the AAA. To our knowledge, this is the first report of successful surgical treatment of a CMT aneurysm and coexistent AAA.