Background:  Body temperature is other biologinal factor , which is known as an important indicator of muscles function. The aim of this study was to investigate the effects of temperature on elbow flexor (Biceps) muscles endurance. Methods: 40 male subjects (22.77±2.11, mean height of 174.99±7.57 cm and mean weight of  63.77±6.45 kg) participated in the present study. The biceps muscles endurance was measured before and after applying ice and hot packs over the forearm for 15 minutes. Results: The results showed a significant increase in biceps muscles endurance after heating. ( r=0.57, p=0.001). it was found  that, cooling the muscles leaded to significant decrease of biceps muscle endurance (P=0.214).Conclusion: These results suggest that elbow flexors  is temperature sensitive. Therefore, further studies are needed to evaluate the effects of Heat and cold on muscular function in people working in workplaces with extreme temperature like many other biological factors, body temperature is known as an important indicator of muscles function.