Supernumerary testis or polyorchidism is a rare congenital anomaly with about 200 reported cases in the literature. It may be associated with cryptorchidism, testicular torsion and neoplasms. Ultrasonography and magnetic resonance imaging are effective noninvasive methods of accurately detecting polyorchidism. In most cases, ultrasonography is diagnostic and magnetic resonance imaging plays confirmatory role by providing additional information if complicated with neoplasia. We report a case of 16-year-old man with right supernumerary testis associated with adenomatous hyperplasia of the rete testis, its sonographic and magnetic resonance imaging findings and management.