Primary mediastinal nonseminomatous germ cell tumor is extremely rare. Apart from rarity and large size, mediastinal germ cell tumors show striking similarity to testicular tumors in age, incidence, and tumor type. The symptoms associated with these tumors are related mainly to size, invasion of neighboring structures, and distant metastases. Tissue diagnosis is obtained by biopsy of the primary lesion or by biopsy of metastatic sites. Tumors often present with advanced bulky disease, which are unresectable. So these tumors require an aggressive multidisciplinary approach to management. Optimal management includes aggressive surgical debulking and early use of cisplatin-bleomycin-based combination chemotherapy. Serial biomarker measurements permit early recognition of recwrence and improved timing of surgical intervention. The prognosis for mediastinal germ cell tumors is poor, not only because they are far advanced at the time of diagnosis but also because some of the tumors-such as embryonal carcinomas, choriocarcinomas, and endodermal sinus tumors-are very aggressive. In these cases, we present three young male patients with large mass on anterior mediastinum. Tissue diagnosis was obtained by primary lesion biopsy. All patients received surgical debulking and combination chemotherapy and experienced a brief response and eventually had relapses. We report these cases with a review of literatures.