OBJECTIVE To analyze the effectiveness of intravenous (IV) tranexamic acid (TA) in reducing blood loss in total knee arthroplasty (TKA). METHODS The population sample was composed of patients with a diagnosis of primary knee osteoarthritis. The patients undergoing TKA were divided in two groups. Group A: comprised patients who used IV TA and B group, formed by patients who did not use TA in the intra or post-operative period. For descriptive analysis, quantitative variables were represented by mean and standard deviations when their distribution was normal and interquartile ranges and medians for non-normal variables. RESULTS The mean age of patients was 68 years old, most of them were female and with involvement of the left knee. Postoperatively patients who had used IV TA showed less bleeding rate and less hemoglobin rate reduction. CONCLUSIONS The use of IV TA in TKA reduces blood loss in peri- and postoperative periods. Regarding total blood loss reduction, hemoglobin rate and need for blood transfusions, IV TA should be used routinely during TKA since it has been shown to be safe with no increase in side effects as thromboembolic events. Level of Evidence III. Retrospective Comparative Study.