Aim:-There is a constant increase in hemodynamic parameters during prolonged tourniquet inflation .We had investigated the effect of low dose 0.5mg/kg bolus ketamine on hemodynamic changes during tourniquet application in lower limb orthopaedic surgeries under general Anesthesia. Method:-100 patients posted for lower limb surgeries under standard general anesthesia using tourniquet were randomly assigned to one of two groups in double blind study. The Group C (control group) received 10 ml saline IV and Group K (study group) received 0.5mg/kg diluted in 10ml 0.9% saline IV given 10 minutes before tourniquet inflation. We had recorded hemodynamic changes, EtCO2 and Et Sevoflurane at 5 minutes interval up to 20 minutes of tourniquet deflation. Inj. Fentanyl 1mcg/kg supplemented if Systolic BP or heart rate raised more than 30% of base line. Results: - Hemodynamic stability was seen statically significant in Group K (p value, < 0.05) at 40, 50 and 60 minutes. Less number of patients needed supplemental fentanyl intra operatively in Group K than in Group C (3 V/s.18 p value <0.05). Conclusion: - Low dose bolus Ketamine 0.5mg/kg prevents tourniquet induced hypertension in lower limb surgery done under general anesthesia.