Varicocele is a common condition, found in many men who present for infertility evaluation. To assess the effect of varicocelectomy on male infertility. A literature search was performed using Embase and Medline. Literature reviewed included meta-analyses and randomized and nonrandomized prospective (controlled and noncontrolled) studies. In addition, a new meta-analysis was performed. Four randomized controlled trials reporting on pregnancy outcome after repair of clinical varicoceles in oligozoospermic men were identified. Using the random effect model, the combined odds ratio was 2.23 (95% confidence interval [CI], 0.86-5.78; p=0.091), indicating that varicocelectomy is moderately superior to observation, but the effect is not statistically significant. We identified 22, 17, and 5 prospective studies reporting on sperm concentration, total motility, and progressive motility, respectively, before and after repair of clinical varicocele. The random effect model combined improvement in sperm concentration was 12.32 million sperm per milliliter (95% CI, 9.45-15.19; p<0.0001). The random effect model combined improvement in sperm total and progressive motility were 10.86% (95% CI, 7.07-14.65; p<0.0001) and 9.69% (95% CI, 4.86-14.52; p=0.003), respectively. These results indicate that varicocelectomy is associated with a significant increase in sperm concentration as well as total and progressive motility. Prospective studies also show that varicocelectomy reduces seminal oxidative stress and sperm DNA damage as well as improving sperm ultramorphology. Studies indicate that a microsurgical approach to a varicocele repair results in less recurrence and fewer complications than other techniques. Although there is no conclusive evidence that a varicocele repair improves spontaneous pregnancy rates, varicocelectomy improves sperm parameters (count and total and progressive motility), reduces sperm DNA damage and seminal oxidative stress, and improves sperm ultramorphology. The various methods of repair are all viable options, but microsurgical repair seems to be associated with better outcomes. Copyright © 2011. Published by Elsevier B.V.