Purpose: To evaluate the outcomes of children with germ cell tumors (GCTs). Methods: Sixty-six children with germ cell tumor diagnosed from 1996 to 2012 were analyzed. Tumor resection was performed in children with teratoma without adjuvant chemotherapy. Malignant GCTs were treated with cisplatin-based chemotherapy and tumor resection. Results: The median age was 4.7 years (range, neonate – 16.9 years). Histopathologic subtypes were immature teratoma in 25, yolk sac tumor in 25, mixed GCT in 5, germinoma in 4, and others in 7 patients. In 35 patients, primary site was gonad. Among remaining patients, primary sites were mediastinum in 12 patients, retroperitoneum in 10 patients, and other sites in 9 patients, respectively. Fifteen patients had metastatic disease, including lung, peritoneum, liver, bone, or bone marrow. The 5-year event-free survival (EFS) and overall survival was 88.1 ± 8.4% and 92.0 ± 6.8%, respectively. The 5-year EFS in patients with GCT in non-mediastinum and in mediastinum was 93.3 ± 3.8% and 66.7 ± 13.6%, respectively ( P=0.003). The 5-year EFS in patients without metastasis and with metastasis was 93.7 ± 3.5% and 71.5 ± 12.2, respectively ( P=0.03). The elevated level of alpha-fetoprotein and beta-human chorionic gonadotropin (b-HCG) at diagnosis did not affect the EFS significantly. In multivariate analysis, risk factor associated with EFS was primary site in mediastinum (HR 21.9, 95% CI 1.7-279.8, P=0.02). Conclusion: Mediastinal GCT, metastasis at diagnosis, and high level of AFP or b-HCG are poor prognostic factors in adults with GCT, showing survival less than 50%. Intensive treatments including first-line high-dose chemotherapy are being considered in patients with these factors. In this study, children with GCT in mediastinum or with metastasis showed poor prognosis; therefore, the patients with these factor need more intensive treatment to improve survival.