A 58-year-old man was found by abdominal echography to have a pancreatic cyst while undergoing a health examination. Later, a multidetector CT and enhanced CT revealed a splenic artery aneurysm. After consultation he was admitted to our hospital for surgery. Multislice CT and magnetic resonance angiography demonstrated a saccular aneurysm, 22 mm in size, located in the proximal portion of the splenic artery. It was resected, and the splenic artery was reconstructed by an end-to-end anastomosis. The patient's postoperative course was favorable, and, after improvement, he was discharged on the 7th postoperative day. As Doppler ultrasound echography is being increasingly used during health examinations, these lesions are being detected with greater frequency. When splenic artery aneurysms rupture, mortality rates increase; we must therefore avoid simplistic observations. There are various treatment strategies available, and we must select which one is appropriate on a case-by-case basis.