Although germ cell tumors are the most common malignancy in young men, extragonadal germ cell tumors are rare. Gastric metastasis presenting initially as upper gastrointestinal hemorrhage is also exceedingly rare. A 27-year-old man presented at our hospital with tarry stool. Gastric fiberscopy images revealed a bleeding gastric polypoid lesion in the anterior wall of the gastric body, from which a biopsy specimen was obtained. Histopathological analysis of the biopsy showed syncytiotrophoblast-like cells with multiple, large nuclei, consistent with choriocarcinoma. Based on these results, our diagnosis was extragonadal retroperitoneal germ cell tumor with gastric metastasis.