Varicocele repair in adolescent remains controversial. Our aim is to identify and combine clinical trials results published thus far to ascertain the efficacy of varicocelectomy in improving testis volume and semen parameters compared with nontreatment control. A literature search was performed using Medline, Embase and Web of Science, which included results obtained from meta-analysis, randomized and nonrandomized controlled studies. The study population was adolescents with clinically palpable varicocele with or without the testicular asymmetry or abnormal semen parameters. Cases were allocated to treatment and observation groups, and testis volume or semen parameters were adopted as outcome measures. As a result, seven randomized controlled trials (RCTs) and nonrandomized controlled trials studying bilateral testis volume or semen parameters in both treatment and observation groups were identified. Using a random effect model, mean difference of testis volume between the treatment group and the observation group was 2.9 ml (95% confidence interval [CI]: 0.6, 5.2; P< 0.05) for the varicocele side and 1.5 ml (95% CI: 0.3, 2.7; P< 0.05) for the healthy side. The random effect model analysis demonstrated that the mean difference of semen concentration, total semen motility, and normal morphology between the two groups was 13.7 × 10 6 ml-1 (95% CI: -1.4, 28.8; P = 0.075), 2.5% (95% CI: -3.6, 8.6; P= 0.424), and 2.9% (95% CI: -3.0, 8.7; P= 0.336) respectively. In conclusion, although varicocelectomy significantly improved bilateral testis volume in adolescents with varicocele compared with observation cases, semen parameters did not have any statistically significant difference between two groups. Well-planned, properly conducted RCTs are needed in order to confirm the above-mentioned conclusion further and to explore whether varicocele repair in adolescents could improve subsequently spontaneous pregnancy rates.