Background and Objectives. The null hypothesis of this study was that TA has no effect on postsurgical bleeding in patients undergoing TKA. Methods. This study was a double-blind randomized trial. In the first group (T) patients received 500 mg of intravenous Tranexamic acid (TA) twice (once preoperatively and once 3 hours postoperatively) and in the second group (P) they received slow infusion of normal saline as placebo. The primary outcome of the study was the level of Hb 48 hours after surgery. Results. Hb levels 48 hours after surgery as the primary outcome were 10.92 ± 0.97 and 10.23 ± 0.98 (g/dL) in groups T and P, respectively, and the difference was statistically significant (P = 0.001). Statistically significant differences were also observed in Hb levels 6 and 24 hours after surgery, the drain output 48 hours after surgery, and the number of units of packed cells transfused between study groups (P < 0.05). There was no significant difference in duration of hospitalization between the study groups (P = n.s.). Conclusions. The low dose perioperative intravenous TA significantly reduces blood loss, requirement for blood transfusion, and drain output in patients undergoing TKA. However, duration of hospitalization did not change significantly.