Abstract Background: Estimation of percentage of change of blood glucose concentration (BGC) at 30- and 60-min after single dose of intravenous midazolam injection and at end of surgery in relation to pre-injection concentration. Aim of Study: Estimation of percentage of changes of blood glucose concentration (BGC) at 30- and 60-min after intravenous injection of single dose of midazolam and at end of surgery in relation to pre-injection BGC. Patients and Methods: 100 type-2 diabetic patients with fasting BGC of ³200mg/dl, ASA grade II or III and assigned for cataract surgery were evaluated clinically and received midazolam injection in a dose of 0. 0 1-0. 1 mg/kg, up to a total dose of 2.5mg, over two minutes or until patient was sedated and achieved Ramsy score 2 or 3. BGC was estimated before midazolam injection and at 30-min, 60-min after injection and at end of surgery. Then, patients received peribulbar and subtenon local anesthetic infiltration was performed. Results: All surgeries were conducted uneventfully within a mean operative time of 62.6±8.8 min. BGC showed progres-sive increases during surgery reaching a maximum at 60-min after injection and declined at end of surgery, but with non-significant differences between the three estimations and the pre-injection levels. Median value of percentage of increase of BGC at 60-min was significantly higher in comparison to median values of other estimations, with significantly higher percentage of increase at end of surgery than at 30-min after injection. Conclusion: Preemptive administration of midazolam for diabetic patients could control the surgery-induced hypergly-cemic effect and thus could protect patients against postoper-ative hyperglycemic complications.