Cisplatin is an anti-cancer drug used in chemotherapy. One of the limiting side effects of cisplatin is decreasing genital gland function, azoospermia and oligospermia. Tribulus terrestris (TT) has been used as an aphrodisiac. The present study amid to investigate protective effect of TT hydroalcoholic extract against cisplatin-induced apoptosis on testis in mice. Male adult mice (n= 30) were divided into control and 4 experimental groups (n= 6). Control group received saline, first experimental group received cisplatin (5.5 mg/kg) and other three experimental group received cisplatin (5.5 mg/kg) and different doses of hydroalcoholic extact of TT (100, 300 and 500 mg/kg/i.p) respectively. Day after the last injection, histopathology and histomorphic analysis and also TUNEL assay on mice testis were performed. Weights of body and testis, seminiferous tubules diameter and apoptotic index were assessed. Data analysis was performed using one-way ANOVA followed by Tukeys’ test. The results showed that cisplatin lead to a reduction in the weight of body and testes, and significantly increased apoptotic index compared to the control group (P<0.001), while in treated groups with TT, the weights of body and testis and seminiferous tubules diameter were significantly higher compared with cisplatin group (P<0.001), but apoptotic index did not show significant differences. The study demonstrates that extract of TT could protective effect of on cisplatin-induced apoptosis of testis and seminiferous tubules diameter that may be related to the presence of antioxidant components acting via a multitude of central and peripheral mechanisms

KEY WORDS: Cisplatin; Tribulus terrestris; Apoptosis; TUNEL.