Autopsy findings in 20 cases of clinical extragonadal germ-cell tumors arising in the anterior mediastinum are presented. The histologic types were: 2 choriocarcinomas, 3 seminomas, 3 malignant teratomas, 3 embryonal carcinomas, and 9 mixed germ-cell tumors. All of the patients were men, and the ages ranged from 14 to 45 years, with a mean of 32.5 years. The mean survival for these patients after diagnosis was 10.9 months. Local recurrence was characteristic of non-seminomatous tumors. In patients with seminoma, local control of the disease was good, but distant metastases were the cause of death. The most frequent sites of metastases were lungs, bones and liver. In all 20 cases, the testes were carefully step-sectioned. Occult tumor was found in only one case of embryonal carcinoma and a well-defined testicular scar with calcification in a patient with choriocarcinoma. Both patients had lower retroperitoneal metastases. These findings support the premise that, in the majority of cases, these tumors had a primary extragonadal origin.