INTRODUCTION: The aim of our study is to compare two different surgical procedures, lymphatic vessels and arterioles sparing microsurgical inguinal varicocelectomy (LASMIV) without delivery of the testis and LASMIV with delivery of the testis and ligature of collateral and gubernacular veins. MATERIALS AND METHODS: Seventy adolescents suffering from varicocele and reduction of the ipsilateral testicular volume greater than 20% were prospectively assigned to two homogenous groups according to age and Tanner stage. The patients, operated from 2008 to 2013, were randomized to undergo either LASMIV without delivery of the testis or LASMIV with delivery and ligature of collateral and gubernacular veins. All patients were evaluated clinically and sonographically 6 months and 12 months after surgery, to measure testicular volume and to rule out any complications or recurrences. RESULTS: The catch up growth of testicular volume is significantly higher at 6 (p value = 0.008) and 12 months (p value = 0.004) in patients treated with LASMIV with delivery. The rate of varicocele recurrence in patients who underwent the delivered maneuver is 0%, whereas is 2.8% without delivery; however this findings is not statistically significant (p value > 0.01). None of the patients of both groups presented secondary hydrocele. CONCLUSIONS: LASMIV with delivery of the testis and ligature of all collateral and gubernaculuar veins results in significantly higher left testicular catch up growth.