Aim: Duodenal metastasis of testicular cancer is an uncommon condition in clinical practice. Here, we have reported a case of this nature. Background: Testicular cancers are among the most seen cancer types among young men. Metastasis of testicular cancer generally occurs through hematogenous and lymphatic drainage. Gastrointestinal (GI) metastasis of testicular cancer has been reported rarely. Case report: A duodenal mass was seen in esophagogastroduodenoscopic examination in a man who was admitted into hospital for medical treatment of resistant nausea and vomiting. He was previously diagnosed with testicular cancer. Computed tomography (CT) views were compatible with primary duodenal tumor. The duodenal mass was compatible with germ cell neoplasm metastasis. He received chemotherapy regime which includes cisplatin, paclitaxel, and ifosfamid. Nausea and vomiting symptoms decreased and metastatic mass and lymph nodes were regressed. Conclusion: Duodenum metastasis of testicular cancer can be treated with a chemotherapy regimen, and patients can improve radiologically and symptomatically without the need of any surgery. Physicians should keep in mind that GI metastasis of testicular cancer may present with nausea and vomiting symptoms.