The purpose of this prospective, randomized, double blind study was to assess the effect of tranexamic acid on blood loss, quality of surgical field and duration of surgery in adolescent orthognathic surgery patients. 50 consecutive patients, scheduled for orthognathic surgery were included. The study group (n=25) received tranexamic acid 10mg/kg as a bolus preoperatively followed by 1mg/kg as a maintenance dose intra operatively; the control group (n=25) received placebo (normal saline). All patients received moderate hypotensive anaesthesia with nitroglycerin and had surgery according to a standard protocol. Intra operative blood loss, duration of surgery, quality of surgical field, blood transfusion and complications, if any, were recorded. The mean total blood loss was 166.1±65.49ml in the study group and 256.4±77.80ml in the control group. The results showed statistically significant reduction in blood loss (p