A 60-year-old man with a history of acute myelogenous leukemia (AML) presented with a complaint of right groin mass. Three years ago the patient underwent an allogeneic bone marrow transplantation. Owing to successful engraftment, remission was achieved for three years. Radiological examinations showed tumor in the groin area along the right spermatic cord (diameter, 30 mm). Right high inguinal orchiectomy was performed. On preoperative tests, there was no other organ metastasis and no recurrence of AML. Pathological examination demonstrated an invasion of AML in the spermatic cord. It was considered that this case was an isolated extramedullary relapse of AML in the spermatic cord after allogeneic bone marrow transplantation. 21 months later, he is alive with no recurrence of AML. Isolated extramedullary relapses of AML after bone marrow transplantation has not been reported, it is possible that this is the first case of metastatic spermatic cord tumor from AML in Japan.