Purpose: Cystic ectasia of the rete testis is a rare condition that may be incidentally noted on scrotal ultrasonography. This benign condition has a typical appearance of a collection of small anechoic structures in the confluence of the mediastinum testis. The main significance of this condition is that it must be differentiated from testicular neoplasm. We reviewed the experience with this condition at our institution. Materials and Methods: A retrospective review was performed to identify all sonograms showing ectatic rete testis performed from 1998 through February 2002. A departmental database was used to identify all scrotal sonograms from this period showing ectasia of the rete testis and clinical correlation was done. These examinations were then reviewed by a single radiologist. Results: We identified 13 cases in the last 4 years. Ultrasound was most commonly performed for a testicular or scrotal mass, or pain. Median patient age was 65 years. All except 1 patient had an underlying condition, including vasectomy, epididymal cyst/spermatocele or inguinal hernia repair, that could cause epididymal or efferent duct obstruction. No patient had a solid testicular mass. Conclusions: Based on clinical and sonographic criteria the diagnosis of cystic ectasia of the rete testis can be made without histological confirmation. Identifying this entity and its associated conditions avoids the need for biopsy or orchiectomy.