Introduction: Thyroid hormone is important for the growth, development and metabolism of the body. A new amount of data show that thyroid hormone influences on pituitary-testis axis. So in this study we investigated the effects of hypothyroidism induction by propiltiouracil (PTU) on serum levels of thyroid hormone, testosterone hormone, luteinizing hormone, follicle stimulating hormone, body and testes weights. Materials and methods: 21 adult male rats divided into three groups. The control group received drinking water induced hypothyroidism groups that they received two doses of propylthiouracil (PTU) were, low dose treatment group, 1mg/100ml in drinking water and high dose treatment group, 10mg/100ml in drinking water, for 42 days. At the end of experiment the animals were weighed and then under anesthesia were sacrificed and serum samples were obtained. Testes gland were weighted and serum levels of hormones were measured by radioimmunoassay. Findings: results showed that PTU decreased levels of T3, T4 (P<0.001(, Testosterone (P<0.001(, body and testes weight (P<0.001) in treatment groups compared to control) effects dependent on dose (. Results did not show any changes of serum levels of LH and FSH in treatment groups. Discussion & Conclusion: This study suggests that induced hypothyroidism, by decreasing in thyroid hormones levels, decreases testosterone level, body and testes weight but does not affect serum levels of LH and FSH. Therefore, hypothyroidism influences on pituitary-testis axis via its effects on testes glands.