Objective: We aimed to compare the efficacy and side effects of propofol, midazolam and alfentanil used for sedation during spinal anesthesia.Methods: Thirty patients aged. 20-70 years, scheduled for inguinal hernia repair, appendectomy or transurethral resection were randomly assigned to three groups (n=10). The patients were given 1.25 mg/kg propofol i.v. in group I, 1.8 |ig/kg alfentanil i.v. in group II and 0.1 mg/kg midazolam i.v. in group III prior performing spinal anesthesia. For maintenance of sedation propofol infusion of 3 mg/kg/h in group I,alfentanil infusion of 40 Jlg/kg/h in group II and midazolam infusion of 0.1 mg/kg/h in group III were started. The infusion rates were adjusted to maintain an appropriate sedation level. In all patients mean arterial pressure (MAP), heart rate (HR), oxygen saturation (Sp02), end tidal carbondioxide (ETC02) and respiratory rate (RR) were recorded.Results: In propofol group; while MAP and HR decreased significantly after bolus dose, the sedation level 2 was achieved within 5 minutes (p<0.05). In alfentanil group; while HR, MAP and RR decreased and ETC02 increased significantly (p<0.05), the desired sedation level was not achieved. In midazolam group; the sedation level 2 was achieved at 15th minute and MAP, Sp02, HR and RR decreased significantly (p<0.05).Conclusion: We conclude that propofol is the most appropriate agent for sedation during spinal anesthesia.