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Introduction & Objective: Adequate and proper hydration during surgery is one of the duties of anesthesiologist. Based on the different effects of dextrose–containing fluids and dextrose-free fluids on the level of blood sugar, we decided to evaluate the effects of these fluids on the blood sugar level after short-term surgeries. Materials & Methods: one hundred patients who were scheduled for elective surgery were randomly divided into two comparable groups and their blood sugar level were measured just before anesthesia and one hour after operation. The first group were hydrated with 1/3, 2/3 fluid and the second group with normal saline or Ringer fluids. The data were analyzed by SPSS software and student T-test. Results: Blood sugar level of both groups were the same before anesthesia but were increased after operation in both groups (the range of blood sugar level were -18 to +54 in group one and -18 to +30 in group two .Hyperglycemia was present after operation in most patients of both groups but the difference between two groups wasn't significant . Conclusion: Dextrose-free fluids can be used during short-term surgeries without any fear of hypoglycemia.