A 7-month-old infant showed bilateral enlarged, nontender scrotal masses. The level of alpha-fetoprotein was greater than 10,000 ng/ml preoperatively; a high left inguinal orchiectomy was performed for a suspected yolk-sac tumor. The right testis was diagnosed as a mature teratoma because it was not possible to establish a line of cleavage between the tumor and the normal tissue, and a high right inguinal orchiectomy was performed. Only one case of bilateral testicular teratomas has been reported in the literature to date. We report a rare second case of bilateral testicular tumors, one a yolk-sac tumor and the other a teratoma.