Polyorchidism is a rare anomaly with approximately 70 cases reported in the literature. We reported a case of polyorchidism with embryonal carcinoma, the first case, in one of 4 testes. Polyorchidism with malignancy had been reported in 5 cases and bilateral polyorchidism in 3 cases. Authors have not been clarified whether the incidence of malignancy in polyorchidism is high or low. But we have to treat the patients with polyorchidism carefully, because polyorchidism is highly associated with cryptorchidism.