Patients with cryptorchidism are at an increased risk for germ cell testicular cancer. OCT 4 has been shown to be a sensitive and specific marker for some types of germ cell testicular cancer. We undertook this study to establish whether OCT 4 immunohistochemistry is a useful tool in the pathohistologic evaluation of postpubertal patients with cryptorchidism. Seventeen postpubertal patients underwent orchidectomy for cryptorchidism at our center since 1997. Immunohistochemical staining with OCT 4 was performed on these samples. Characteristic OCT 4 nuclear staining was positive in two patients. One patient was correctly diagnosed on previous pathohistological evaluation, while OCT4 immunohistochemical staining revealed previously unidentified intratubular germ cell neoplasia in the other patient. OCT 4 immunohistochemistry can be useful in diagnosing a testicular germ cell tumor in patients with cryptorchidism. If we consider a low number of postpubertal patients with cryptorchidism a benefit of immunohistochemical staining with OCT4, this could favor the use of OCT 4 staining in work-up of cryptorchidism.