Objective To investigate the clinical and pathological features, optimal treatment and prognostic factor in primary mediastinal germ cell tumors （PMGCT）. Methods The clinical presentation, pathological features and therapeutic results of 29 patients with PMGCT were retrospectively analyzed. Results All the 29 patients were male with a mean age of 26.1 ± 9.6 years at diagnosis. All tumors were originated from the anterior mediastinum with a mean diameter of 16.0 ± 5.2 cm. There were 5 （ 17.2% ） primary mediastinal seminomas （PMSGCT） and 24 （82.8%） primary mediastinal nonseminomas （PMNSGCT） in this series. Dyspnea, cough and chest pain were the most common symptoms. Muhimodality treatment consisting of cisplatin-based chemotherapy, surgery and radiotherapy was the principal therapy for PMGCT patients. The median survival of the 24 PMNSGCT patients was 19.0 months with 1-, 2-year survival rate of 65.3% and 28. 1% , respectively; whereas the median survival of the 5 PMSGCT patients has not reached but longer with significant differences （ P = 0. 008 ）. Cox multivariate analysis indicated that limited mediastinal disease at diagnosis （ P = 0. 004 ） and the use of cisplatin-based combined chemotherapy （ P = 0.005 ） were independent good prognostic factors of PMNSGCT . Conclusion Primary mediastinal nonseminoma constitutes the most of primary mediastinal germ cell tumors. Cisplatin- based combined chemotherapy may be the most effective for the treatment of primary mediastinal germ cell tumors. The prognosis of primary mediastinal nonseminomas is significantly worse than that of primary mediastinal seminomas, and correlated with the extent of disease and chemotherapy.