In this study, we aimed to evaluate the effect of oral antioxidant treatment on semen parameters and pregnancy rates in infertile men who underwent varicocelectomy. The study was conducted between January 2016 and January 2018. Subinguinal microscopic varicocelectomy was performed in 90 patients who were referred for infertility and diagnosed with clinical varicocele. The patients were divided into two groups. The first group received antioxidant treatment for 6 months after the operation (n = 62); the second group did not receive treatment after the operation (n = 28). The semen analysis was performed at the time of diagnosis and at 6 months postoperatively. The postoperative treatment semen parameters and pregnancy rates between the two groups were compared. The improvement in total sperm count ( + 45.9% vs + 26.8%), total motile sperm count ( + 50.6% vs + 29.7%), sperm concentration ( + 71.4% vs + 54.5%), sperm count in normal morphology ( + 75.7% vs + 39.9%), and total ( + 28.6% vs + 18.3%) and progressive motile sperm count ( + 60.4% vs + 38.9%) were significantly higher in the treated group than in the untreated group (p = 0.011, p < 0.001, p = 0.008, p < 0.001, p = 0.024 and p < 0.001, respectively). The clinical pregnancy rate in the first group was significantly higher than that in the second group (29% vs 17.9%) (p = 0.029). We concluded that the antioxidant treatment provides an important contribution to varicocelectomy outcomes and improves pregnancy rates.