BACKGROUND Timely diagnosis and treatment of intra-abdominal arterial aneurysms before rupture are highly recommended. We successfully prevented rupture through arterial aneurysm excision, highlighting the importance of the lack of reports on resection before rupture. METHODS A 60-year-old male with previous history of ureteral stones presented complaining primarily of left-sided abdominal pain. Computed tomography (CT) revealed a left ureteral stone and incidentally identified a submucosal gastric tumor and right gastric artery aneurysm, leading to referral to our department. Blood tests showed no abnormalities. CT revealed a 23-mm submucosal tumor protruding outward from the middle gastric body wall. A 13-mm aneurysm was observed in the right gastric artery, and no other aneurysms were detected, including intracranially. Upper gastrointestinal endoscopy revealed a smooth elevation covered by normal mucosa in the middle gastric body. Endoscopic ultrasound-fine needle aspiration resulted in a diagnosis of gastrointestinal stromal tumor (GIST) and surgery. We performed simultaneous surgery involving laparoscopic local resection of the gastric GIST and identification and excision of the right gastric artery aneurysm due to its enlargement (7 mm on CT conducted six years ago). The patient's postoperative course was uneventful, and he was discharged on postoperative day 6. Pathological examination confirmed a diagnosis of segmental arterial mediolysis. CONCLUSIONS Intra-abdominal arterial aneurysms affect approximately 1 % of the population. Splenic artery aneurysms are the most common at 58.7 %, whereas the gastric artery and gastroepiploic artery account for only 4.7 %. CONCLUSIONS Right gastric artery aneurysms are exceedingly rare, with no reported cases of successful resection before rupture.