Although testicular germ cell tumors have become curable neoplasms, a better understanding of the clinicopathologic features is needed for the rare manifestations associated with treatment failure. We report a rare case of metastatic pure choriocarcinoma involving the small intestine arising from a testicular mixed germ cell tumor. In a patient who developed massive upper gastrointestinal hemorrhage during treatment, the intestinal metastases and focus of bleeding could only be determined by laparotomy. We propose an approach for the determination of subclinical intestinal metastases of testicular germ cell tumor; the case is discussed in light of similar reports in literature.