Purpose: We aimed to search the effects of different dosages of dexametazone on blood glucose, serum electrolytes and postoperative nause and vomiting given for reducing brain edema to the patients undergoing craniotomy for intracranial tumors. Materials and methods: Sixty-eight patients, scheduled for elective craniotomy were randomized into 4 groups as: 4 mg dexametazone group, 8 mg dexametazone group, 16 mg dexametazone group and control group. Intravenous dexametazone was applied to the patients after tracheal intubation. Blood samples were taken from the patients and the level of blood glucose and serum electrolytes were measured. All patients were evaluated in terms of postoperative nause and vomiting for 24 hours. Results: Comparisons between groups showed that, the blood glucose levels in all groups at the 240th min were significantly higher than basal levels (p<0,05). There were no statistical differences between the groups with regard to the mean blood glucouse levels and serum electrolytes. Postoperative nause and vomiting at 0-6 hours was lower in dexametazone group than the control group and the decrease at 2-6 hours was statistically significant. Conclusion: Dexametazone has minimal effects on blood glucose and serum electrolyte levels and decreases postoperative nause and vomiting in the first 6 hours after craniotomies.