Epithelial ovarian carcinoma rarely metastasizes to the parenchyma of the stomach. A 55-years-old woman presented with epigastric pain and a feeling of fullness for one month. A subsequent contrast-enhanced CT scan demonstrated a 4.5 × 4 cm submucosal mass with focal ulceration in the gastric antrum, and this finding was suggestive of GIST. After gastric antrectomy, the final pathology showed metastatic gastric tumor from a primary ovarian serous carcinoma. Because epithelial ovarian carcinoma is usually spread along the peritoneal surface, stomach involvement is rare. Furthermore, transmural gastric metastasis is very rare in a patient with primary ovarian carcinoma. Until now, there has been no reported case of stomach involvement at presentation in a patient with primary ovarian carcinoma. We present here a case of ovarian carcinoma with gastric metastasis that mimicked GIST.