Polyorchidism is a rare anomaly. Approximately 70 cases have been reported in the literature. It may result from transverse division of the uro-genital ridge, an hypothesis which best accounts for the anatomic features of the supernumerary testicle. 53 cases are reviewed and two more are added. Main accompanying disorders and anomalies include maldescended testis, inguinal hernia and torsion. Malignancies are reported in three cases. In the absence of any concomitant disorder, and if testicular tumor can be ruled out by magnetic resonance imaging (MRI) and ultrasonography, surgical exploration ith biopsy may be omitted.