Malignant germ cell tumors are relatively uncommon, accounting for approximately 3% of all childhood malignancies. Occurring with an incidence of approximately 4 per million among children less than 15 years of age, they account for approximately 225 new cases per year in the United States. Germ cell tumors occur in both gonadal and extragonadal sites, with extragonadal and testicular tumors predominating in children less than 3 years of age and with the gonads being the main location of tumors during and after puberty. They occur more frequently in girls than boys. Germ cell tumors are interesting for several reasons: (1) abnormal migration of primordial germ cells account for many of the childhood germ cell tumors; (2) markers exist to allow evaluation of the extent of resection and the development of recurrence for many of the tumors; and (3) the introduction of platinum-based chemotherapy has markedly improved the survival rate for germ cell tumors, as well as the salvage rate for recurrent or metastatic disease.