The clinical and pathologic features of germ cell tumors in 188 patients seen at the Childrens Hospital of Los Angeles from 1941 to 1986 are reviewed. There were 129 females and 59 males 19 years of age or younger. Tumors were seen in the ovary (73, 39%), sacrococcygeal region (67, 36%), testis (13, 7%), pineal region (10, 5%), mediastinum (8, 4%), and other sites (17, 9%). The mean age at diagnosis of patients with sacrococcygeal tumors was 11 months, and for those with ovarian tumors it was 9.3 years. Histologically, 56% of the tumors were benign, 15% had immature tissues, and 29% had frankly malignant tumors. Patients with immature tumors and elevated serum alpha-fetoprotein levels at diagnosis had a higher incidence of tumor relapse (p = .004). The histology of the recurrent tumors in these patients was embryonal carcinoma. Of 54 patients with malignant tumors, 27 are alive with no evidence of recurrence, 5 died of non-disease-related causes, and 22 (41%) had tumor recurrence within 3 years of initial diagnosis and eventually died of tumor progression. The 5-year survival rate for patients with benign tumors was 96%; for those with immature tumors, 83%; and for those with malignant tumors, 42%.