We report a case of a testicular teratoma located in the opposite side of the upper abdominal wall. A 2-year-old boy presented with a non-palpable right testis and underwent right inguinal exploration for right cryptorchidism. During surgery, the tumor was found in the opposite side of the upper abdominal wall across the midline. Histological investigation of the tumor revealed a mature teratoma occurring in the intra-abdominal testis. No such case has been previously reported.