Fifty-one primary intracranial germ cell tumors (GCT), including germinoma, teratoma, endodermal sinus tumor, choriocarcinoma and mixed GCT, were studied. The incidence of GCT in the surgically removed intracranial neoplasms was 11.1% for pediatric patients and 0.6% for adult patients. The age/sex of the patients and the location of the tumors were analyzed. Morphologic findings of these tumors were identical to that of their gonadal counterparts. Immunohistochemical studies showed that alpha-fetoprotein (alpha-AFP), human chorionic gonadotropin (HCG), and placental alkaline phosphatase (PLAP) were helpful, whereas carcinoembryonic antigen (CEA) and cytokeratin (CKER) were of little help in determining the diagnosis. Serum tumor markers, alpha-AFP and HCG, were helpful in recognizing GCT producing them. However, they could not be used for specific diagnosis because different tumors could have similar serum levels. Histopathologic study was handicapped by the small size of most specimens (which usually could not include all of the components if the tumor was a mixed GCT), but it was the only means for specific diagnosis.