Abstract Study question Can varicocelectomy be indicated for the treatment of hypogonadism in men above 40 years of age? Summary answer Varicocelectomy improves serum testosterone (T) levels in men with preoperative hypogonadism. This improvement can be anticipated in men above the age of 40 years. What is known already Varicocele ligation is a common intervention used to restore male fertility potential and enhance conception rates. Few studies reported a favorable effect for varicocelectomy on serum T levels stirring some scientists to indicate treatment for men with late onset hypogonadism. Nonetheless, data is still scarce for such a recommendation highlighting the importance of this work Study design, size, duration The charts of 1696 patients who underwent microsurgical subinguinal varicocelectomy for clinically palpable disease between 2011-2023 were retrospectively reviewed. Patients with available pre- and post-operative serum hormone levels were included in the study while those receiving any form of androgen replacement or induction treatment or with known secondary causes of hypogonadism were excluded. Participants/materials, setting, methods Medical charts were reviewed to collect demographic and clinical data. Patients were classified into 2 groups according to preoperative T levels: hypogonadism group (serum T < 10.4 nmol/L) (n = 226) and eugonadal group (serum T ≥ 10.4 nmol/L) (n = 1469). The hypogonadism group was subclassified according to age into less (n = 161) or ≥ (n=66) 40 years of age. Changes in hormone levels were analyzed using Wilcoxon Signed Ranked. A p value <0.05 was considered significant. Main results and the role of chance The patients mean age was 33.6 ± 8.5 years. Their mean BMI was 27.2 ± 5.8 Kg/m2, mean left testis size was 13.4 ± 3.5 cm3 and right testis size 14.4 ± 4.5 cm3. The maximum left and right vein diameters was 3.9 ± 1.3 mm and 2.46 ± 0.73 mm. Unilateral and bilateral microsurgical varicocelectomy were performed in 82% and 18% of cases, respectively. Post-operatively, no significant changes were observed in hormone levels in comparison to preoperative values in the eugonadal group. However, patients with preoperative hypogonadism had significant increase in serum T (7.7±2.2 vs 11.7±6.6, p < 0.001) and E2 (72.5±31.3 vs 94.8±42, p < 0.001) levels following the intervention. These significant improvements were observed in both men < 40 years of age (p < 0.001 for both T and E2) and ≥ 40 years of age (T: p = 0.027, E2: p = 0.024). Limitations, reasons for caution Results were obtained from a retrospective chart review. The majority of these patients performed surgery for fertility reasons and data regarding hypogonadism symptoms is lacking. Wider implications of the findings Results of this study further confirm that an increase in serum testosterone is likely to be anticipated in patients undergoing varicocelectomy who have low serum testosterone levels pre-operatively Trial registration number not applicable