Nanoparticles for their special and unique features are widely used in different industries such as medicine and pharmaceutical. In addition to positive aspects of gold nanoparticles, its toxicity in environment is unavoidable. This study was conducted on 40 Wistar rat, divided in 5 groups including a control, a sham and three other experimental groups. The control group was treated daily with 0.5 cc saline solution, the sham group had food and water, and three other groups received intraperitoneal injection of 0.5 cc gold nanoparticles at different doses (100, 50, 25 ppm). After 10 days of treatment, animals were anesthetized; blood samples were collected from the heart and luteinizing hormone (LH), follicle–stimulating hormone (FSH), and testosterone (T) were measured. Testes were removed and preserved in formaldehyde (10%) solution. For statistical analysis, the analysis of variance (ANOVA) and Dunnett test were performed by SPSS software, version19. Results showed that gold nanoparticles have significant effect on hormones in concentrations of 100 ppm. LH, FSH and testosterone were significantly increased compared to (P<0.05). Seminiferous tubular degeneration was also observed in the testes. These findings suggest that gold nanoparticles may cause an increase in hormones in female and in male with subsequent increase in sterility.