BACKGROUND Doxorubicin (DOX), an anthracycline antibiotic, is a widely used anticancer agent. In spite of its high antitumor efficacy, the use of DOX in clinical chemotherapy is limited due to diverse toxicities, including gonadotoxicity. OBJECTIVE We investigated the protective effect of nano-zinc oxide (nZnO) as an established antioxidant on DOX-induced testicular disorders. METHODS In this experimental study 24 adult male Wistar rats were divided into four groups including one control and three experimentals (6 rats per group). They received saline (as control), DOX alone (6 mg/kg body weight, i.p.), nZnO alone (5 mg/kg body weight, i.p.), and nZnO followed by DOX. Animals were sacrificed 28 days after treatment and evaluations were made by sperm count and measuring sex hormone levels in plasma. Also total antioxidant power (TAP) and lipid peroxidation (LPO) in plasma were tested. Data was analyzed with SPSS-14 and one way ANOVA test. P<0.05 were considered to be statistically significant. RESULTS In the DOX-exposed rats significant differences were found compared with the control group (p=0.001) in plasma total antioxidant power (TAP) (425.50±32.33 vs. 493.33±18.54 mmol/mL), Lipid peroxidation (LPO) (3.70±0.44 vs. 2.78±0.68 μmol/mL), plasma testosterone (3.38±0.69 vs. 5.40±0.89 ng/dl), LH (0.26±0.05 vs. 0.49±0.18 mlU/mL), sperm count (157.98±6.29 vs. 171.71±4.42×10(6)/mL) and DNA damage (11.51±3.45 vs. 6.04±2.83%). Co-administration of nZnO significantly improved DOX-induced changes (p=0.013) in plasma TAP (471.83±14.51 mmol/mL), LPO (2.83±0.75 μmol/mL), plasma testosterone (5.00±1.07 ng/dl), LH (0.52±0.08 mlU/mL), sperm count (169.13±5.01×10(6)/mL) and DNA damage (7.00±1.67%). CONCLUSIONS At the dose designed in the present investigation cytoprotective role of nano-zinc oxide through its antioxidant potential is illuminated in DOX-induced male gonadotoxicity.