The hormonal and metabolic changes which follow injury or surgery. Insulin concentration may decrease after the induction of anesthesia and during surgery. Acute hyperglycemia makes the patient's hospital stay longer and later discharge and more expenses, so controlling hormonal changes can be useful for patient, physician and health system either. We conducted this study to find an easy and available way to getting this aim. 80 patients, ASA I and II were allocated in to two groups randomly. Patients in first group received 5mg oral Diazepam with 50cc water at the night before surgery and in the morning of surgery. Patients in control group received no drugs. Blood samples were taken before anesthesia induction and 15min after induction. They were sent to the lab to measure blood sugar level. The data was analyzed using t Student and Chi square test with SPSS software. Rang of pre anesthesia blood sugar in study group were 68-118 mg/dl and in control group was 80-131 mg/dl. These values in intra operative phase in first group were 67-110mg/dl and in control group were 90-131mg/dl (P<0.0001). These results supported that using oral Diazepam as a premedication drug attenuates the hyperglycemic response due to surgical stressinduced release of Catecholamine and Cortisol. So the less hormonal changes, sooner patient discharge, fewer occupied beds in hospitals and less expenses for patients, hospital and health system.