To investigate the potential protective effects of losartan on varicocele-induced germ cell apoptosis, 24 adult male Sprague Dawley rats were divided into three groups: a sham operation was performed in SHAM group, and experimental left varicocele was created in VAR and VAR+LOS groups. Additionally, in VAR+LOS group, losartan was administered for 30days starting on the day of surgery. At the end of 30days, all animals were sacrificed and left orchiectomy was performed. Testicular injury and spermatogenesis were evaluated according to Johnsen scoring system. To assess the nitrosative stress, immunohistochemical staining for endothelial nitric oxide synthase was used and evaluated by H-score and apoptotic index (AI) of germ cells was analysed by TUNEL method. A significant decrease in the mean Johnsen score (JS) was observed in VAR group compared with SHAM (p<.001). The mean H-score and AI were significantly higher in VAR group compared with SHAM (p<.001). After losartan administration, mean JS was significantly increased (p<.001) and mean H-score and AI were significantly decreased compared with VAR group (p<.001 and .01, respectively). Findings of this suggest that losartan acts as a potent protective agent against varicocele-induced germ cell apoptosis.