Splenic artery aneurysms (SAAs) are relatively rare. Moreover, there has been only one previous report of fibromuscular dysplasia (FMD) affecting the splenic artery alone. We describe a 64-year-old man with long, segmental, large, and multiple SAAs in whom the splenic artery branched from the aorta. The patient underwent endoaneurysmorrhaphy and splenectomy, with ligation in the proximal segment of the splenic artery. Histopathological analyses of resected specimens showed characteristics compatible with FMD. To our knowledge, long, segmental, large, and multiple SAAs caused by FMD have not previously been reported.