Nonylphenol (NP) has been found to exert estrogenic effects on organisms and thus interfere male reproductive behavior. Therefore, the present study was conducted to evaluate the effects of nonylphenol on defense antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and glutathione reductase (GR). Moreover, its effect on testosterone and gonadotropin hormones (FSH, LH) on testies of rats was studied. Also the effect of nonylphenol on sperm characteristics was investigated. Adult male rats were divided into four groups: one group was gavaged with NP dissolved in corn oil, second one is the control group rats which were gavaged with corn oil alone, vit. E. alone was administrated to the third group and the last group was gavaged with a combination of vit. E. and NP. These treatments lasted 30 days. The activity levels of the SOD, CAT, GR and testosterone were significantly decreased in NP treated rats when compared to the control group, while the MDA and gonadotropins were significantly increased. Moreover, sperm count, motility and viability were significantly decreased in this treated group. Vit. E caused significant recovery on the different measured parameters once combined with the nonylphenol. In conclusion, this study revealed that NP treatment impairs spermatogenesis and has estrogenic potential which disrupt antioxidant balance which leads to oxidative stress. This study also supports the significance of vit. E. as an antioxidant.