A variety of regimens of high-dose chemotherapy with hematopoietic stem cell support for poor risk germ cell tumors have been established. However, a series of chemotherapy steps carried out prior to the harvest sometimes leads to an insufficient number of peripheral blood stem cells. Here, we report a case of a patient who successfully underwent high-dose chemotherapy for the treatment of poor risk extragonadal germ cell tumor by receiving peripheral blood stem cell transplantation donated from his genomically identical twin brother.