Testicular varicocele is the single most common cause of male infertility. Varicoceles are due to either absent or nonfunctioning valves that permit retrograde flow in the internal spermatic vein resulting in increased temperature within the scrotum and interfering with spermatogenesis. Our method to treat varicoceles is occlusion of the spermatic vein with detachable silicone balloons. In our first 70 patients, this has proven to be a safe and effective nonsurgical method of occluding varicoceles in outpatients with results similar to those of surgery.