Background: Discopathy is one of the most common spinal surgeries. Hemodynamic control is important in bleeding reduction during the surgery. Clonidine and dexmedetomidine both are α agonists that help stabilize hemodynamics and prevent the increase of intraoperative bleeding. Objectives: In this study, the effects of clonidine and dexmedetomidine were compared in bleeding reduction during spinal surgery.Methods: This randomized, double-blind clinical trial was conducted in 120 patients aged 20 to 50 years with ASA class I or II, undergoing spinal surgery. Patients were randomly divided into three groups. Group C received oral clonidine 0.2 mg, 90 minutes before entering the room. Group D received dexmedetomidine 0.5 µ/kg 15 minutes before anesthesia induction and 0.25 µ/kg/h infusion during operation. Group P received placebo as the control group.Results: There was a significant reduction in intraoperative blood loss in patients who received clonidine (289 ± 130) and dexmedetomidine (344 ± 145) compared to the control group (462 ± 15) (P < 0.05), with a more dramatic reduction in the clonidine group (P < 0. 001).