Gastric mucosal calcinosis (GMC) is a rarely encountered disease characterized by calcific deposition in the gastric mucosa which was known to be associated with organ transplantation, end-stage renal disease, hypercalcemia, hyperphosphatemia, gastric neoplasia, medications such as antacids containing aluminum, sucralfate and bismuth, and so on. We describe incidentally found 23 cases of GMC. Methods: We identified 23 cases of GMC from July 2004 to June 2011 from pathology department records. All available inpatient and outpatient medical records including laboratory data were reviewed. Results: 23 cases (9 male and 14 femal: median age of 65.2, range 34-85) were found incidentally by upper gastrointestinal endoscopic biopsy. The microscopic examination showed multifocal basophilic calcific material just beneath the surface epithelium. 14 patients (60.9%) were taking tripotassium dicitrato bismuthate in variable duration from one week to four years, 5 patients (21.7%) were taking aluminum containing antacid and 2 patient (8.7%) were taking both of them. 1 patient (4.3%) showed hypercalcemia with increased parathyroid hormone. The patients had no history of renal insufficiency, organ transplantation or gastric malignancy and had variable symptoms according to other comorbid gastrointestinal diseases, in example, gastritis, gastroesophageal reflux disease, and functional dyspepsia. The endoscopic findings were hyperemia, edema, chalky or salty-white plaque in common and other frequently accompanying feature was spontaneous bleeding. However, endoscopic finding of 2 pateints (8.7%) showed gastric polyp which confirmed GMC pathologically. There was no difference of endoscopic findings between different etiologies. Follow up endoscopy which was available in 8 patients (34.8%) from two months to two years after stopping offending medication showed disappearance of previous noted GMC. Conclusion: Gastric mucosal calcinosis can develop in normal tissue because of altered serum or mucosal biochemical environment associated with therapeutic measures and can be reversed after abstinence of the offending medication.