Varicocele is a common disorder in men characterized by abnormal dilation and tortuosity of the pampiniform venous plexus, often leading to testicular dysfunction. This study evaluated the protective effects of melatonin on serum testosterone levels, testicular histopathology, B-cell lymphoma 2 (BCL-2) gene expression, and platelet indices in experimentally induced varicocele in rats. Twenty-four adults male Wistar rats (7 weeks old) were randomly divided into four groups (n = 6): Control (sham-operated + saline), VC (varicocele-induced + saline), MEL (sham + melatonin 5 mg/kg orally), and VC-MEL (varicocele-induced + melatonin 5 mg/kg for 4 weeks). Body weight (BW1, BW2), testes weight (TW), hormone levels, BCL-2 mRNA expression, and platelet parameters were analyzed. The VC group showed the greatest BW2 reduction and lowest TW (213.84 g and 0.604 g, respectively), along with the lowest BCL-2 expression (0.102) and testosterone levels (0.87 ng/ml). Histologically, only spermatocyte cells were observed in this group based on Johnson's score. The control group had the highest platelet count (PLT: 241.004 ×10³/µl), while the VC group exhibited elevated PCT (0.42%), MPV (5.96 fL), and PDW (18.4%). Melatonin administration significantly improved all measured parameters, likely due to its antioxidant and anti-inflammatory properties. It enhanced testosterone production, upregulated BCL-2 expression, improved testicular histology, and normalized platelet indices. These findings suggest that melatonin may offer therapeutic benefits in managing varicocele-related damage in experimental models.