Gastric carcinoid tumors associated with chronic atrophic gastritis type A have been reported to show good prognosis, because invasion and metastasis are rare. We report a case of gastric carcinoid tumor associated with hypergastrinemia that showed no malignant changes for 12 years. A 15-year-old man with abdominal discomfort underwent endoscopic examination. A polypoid lesion was detected on the atrophic mucosa of the fundus, and was diagnosed as a carcinoid tumor. Serological examination revealed a high level of anti-parietal-cell antibody, suggesting that the patient had chronic atrophic gastritis type A. The tumor was treated by endoscopic mucosal resection. Follow-up examinations were performed for 12 years, but showed no recurrence. This case confirms that gastric carcinoid tumors associated with chronic atrophic gastritis type A may have a good prognosis.