A varicocele is a dilatation of the testicular vein and the pampiniform venous plexus within the spermatic cord. Although rare in pediatric populations, the prevalence of varicoceles markedly increases with pubertal development. Varicoceles are progressive lesions that may hinder testicular growth and function over time and are the most common and correctable cause of male infertility. Approximately 40% of men with primary infertility have a varicocele, and more than half of them experience improvements in semen parameters after varicocelectomy. The decision to treat adolescents with varicocele is a controversial one. The task for pediatricians and urologists is to identify those adolescents who are at greatest risk for infertility in adulthood, in an effort to offer early surgical intervention to those most likely to benefit.