In this review, we discuss varicocele testis, which is found in 15% of men from the general population, but more frequently in infertile populations. It can cause physical symptoms or impaired fertility. Varicocele severity is graded 1-3 by clinical examination, and increasing grade is associated with poorer semen quality. Treatment effect on symptoms and fertility has been documented. A microsurgical approach seems to have the best outcome in terms of lowest frequency of recurrence and complication. Treatment of this common condition is recommended only in patients with symptoms or evidence of affected testicular function.