We investigated the role of the tumor suppressor genes in the germ cell tumor. Immunohistochemistry (IHC) and polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) for p53 mutation were done in 46 cases of the germ cell tumor with paraffin embedded tissue. The immunohistochemical staining for Rb protein was also performed in the same specimens. The following results were obtained. The overexpression of the p53 protein was detected in 7 of 46 cases (15%). p53 mutation by PCR-SSCP was detected in 1 of 46 cases (2.2%). Expression of Rb protein was negative in 19 cases (41%). These results suggest that p53 mutation does not play an important role in the initiation and progression of germ cell tumors.