Summary In this study, we aimed at investigating the impact of melatonin supplementation on semen parameters, hormonal profile and total antioxidant capacity after varicocelectomy. Infertile male patients who were diagnosed with varicocele and underwent subinguinal varicocelectomy were included in the study. After performing subinguinal varicocelectomy, the patients were randomised into two groups: 27 receiving melatonin for 3 months and 27 as the placebo‐controlled group receiving placebo for 3 months. The pre‐operative parameters of semen analyses, hormonal profile and seminal oxidative stress status of both groups were compared with those of post‐operative parameters. There were statistically significant improvements in post‐operative parameters of semen analyses (sperm concentration, motility and proportions of normally formed spermatozoa), peripheral blood inhibin B and total antioxidant capacity in melatonin group compared with placebo group. In conclusion, melatonin therapy adds extra benefit to varicecelectomy in terms of sperm parameters, peripheral blood inhibin B and total antioxidant capacity; however, further studies including large number of samples are needed to make a proper decision on melatonin supplementation after varicocelectomy.