Background: in orthopedic procedures more blood is lost from raw bone and muscle surface than from identifiable blood vessels. Moderate hypotensive anesthesia was found to significantly decrease the average blood loss by nearly 40%, reduce the need for transfusion by 45% and shorten the average operating time by nearly 10%. Objective: The aim of the current study was to compare magnesium sulphate and dexmedetomidine with nitroglycerin as regard hypotensive effect as primary outcome, volume of blood loss, blood substitution and pattern of recovery as secondary outcome during lumbar spine surgery. Patients and Methods: This prospective, controlled, comperative, randomized, double blind study included a total of ninty patients aged 21-50 years of both sex, ASA I-II scheduled for elective lumber spine surgery, attending at Department of Orthopedic, AL-Azher university Hospital in Assuit as single center study. Patients have received either dexmedetomidine, magnesium sulfate or nitroglycerine. Results: There were highly significant difference (P <0.000) with duration of surgery between different study groups with duration of surgery shortest in dexmedetomidine group followed by magnesium sulfate group and then nitroglycerine group. There were highly significant differences between different study groups with fluid maintenance with higher volume in nitroglycerine group then magnesium sulfate group and then dexmedetomidine group. There were highly significant differences (P <0.000) with systolic blood pressure between study groups at A1 and hypotensive agent discontinuation with lowest systolic blood pressure in dexmedetomidine group followed by magnesium sulfate group and then nitroglycerine group. Conclusion: nitroglycerine, magnesium sulfate and dexmedetomidine could induce hypotension, but dexmedetomidine showed more favorable hemodynamic profile as regard blood pressure and heart rate.