In the present study, the role of testicular androgen in fasting induced glucose and FFA changes in rats was investigated. The study showed that testicular androgen plays a significant role in the regulation of glucose met¬abolism. The role is protective in nature against hyperglycemia, as castra¬tion elevates the lasting blood glucose level. On the other hand, the role of testicular androgen in fasting induced FFA changes is probably enhancing their mobilization to the serum. This is evidenced by the decrease in the fasting FFA level in castrated rats.