Background: Varicocele repair has been advocated as an option to prevent and treat low serum testosterone, even in men with normal semen quality. The association between clinical varicocele and impaired testosterone production is less clearly understood. Although, the conceptions of the negative impact of clinical varicocele on Leydig cell functions and the beneficial effect of varicocele repair on testosterone production have been proposed for decades. Objective: To examine the hypotheses that clinical varicoceles affect baseline serum total testosterone levels and to study the effects of varicocelectomy on serum testosterone levels and semen quality in infertile men who suffer from varicocele. Patients and Methods: This study included 100 patients (50 control and 50 cases) presented to the General Surgery and Endocrine Surgery Unit Outpatient Clinic at Mansoura University Hospitals with clinical varicocele for primary infertility. The study was conducted during the period between 1^st April 2020 and end of March 2021. Results: Regarding preoperative and postoperative testosterone level among the intervention group, there were highly statistically significant increases in total testosterone as well as significant improvement in gonadal functions (significant increase in number of cases with euogonadism) after the operation among the intervention group (P < 0.001). however the percent of improvement was more than among hypogonadal compared to euogonadal. Conclusion: Varicocelectomy was demonstrated to significantly improve both sperm quality (in terms of volume, count, motility and morphology) as well as serum testosterone in infertile men, especially in cases with hypogonadism.