An eight year old female dog was referred with anorexia, nervousness and emaciation. At the point of time, severe lifelessness was the only symptom. Then euthanasia was done according to the owner’s decision. As a result of postmortem examination, thin white matters were found on the gastric mucosa of the greater curvature and there were no other significant gross findings. Tissue specimens were collected from the gastric wall, esophagus, gall bladder, aorta, heart, kidneys, liver, mesenteric lymph node, lungs, urinary bladder and spleen and processed for histopathology. Microscopically, the masses of stomach were consisted of well-differentiated osteoid tissues, the compact bone-osteocytes and the matured lamellated bone with Haversian system. It was diagnosed as osteoma of the stomach. Other organs were free on such histological findings.