A 72-year-old Japanese man presented with a painless swollen left scrotal mass with elevated levels of serum alpha-fetoprotein and prostate specific antigen. The patient underwent high orchiectomy under diagnosis and a final pathological examination revealed embryonal carcinoma of the left testis. A systematic needle prostate biopsy under guidance of transrectal ultrasound revealed prostate cancer (Gleason score, 8) on the left lobe (T2aN0M0). Systemic chemotherapy was given for retroperitoneal lymph node metastasis of testicular cancer and hormonal therapy (LH-RH analog) was given for prostate cancer. The patient was well with no evidence of metastasis from the testicular cancer or prostate cancer and with no elevation of serum alpha-fetoprotein or prostate specific antigen 26 months after the orchiectomy.