Résumé : The benefit-to-risk ratio of using tranexamic acid (TXA) in paediatric cardiac surgery has not yet been determined. This systematic review evaluated studies that compared TXA to placebo in children undergoing cardiac surgery. A systematic search was conducted in all relevant randomized controlled trials. The following information was extracted from the studies and analysed if relevant: demographic data, TXA dose and regimen of administration, cardiopulmonary bypass time, blood loss and blood product transfusion at 24 h. From the studies screened, only 8 (848 patients) were included in the analysis. Most data were heterogeneously distributed and could not be analysed. Further, transfusion policies were not well defined for each study. TXA reduced the need for red blood cell transfusion by 6.4 ml kg-1 day-1 (I2 = 0%, P = 0.45), platelet transfusion by 3.7 ml kg-1 day-1 (I2 = 0%, P = 0.46) and fresh frozen plasma transfusion by 5.4 ml kg-1 day-1 (I2 = 0%, P = 0.53). The number of children who avoided all blood product transfusions was not reported in most of the studies. Evaluation of the side effects associated with TXA use and the effects of the agent on postoperative morbidity and mortality was not possible from the data. There was marked variability in the dosage and infusion schemes used in different studies. This systematic review showed that in paediatric cardiac surgery, the benefit-to-risk ratio associated with the use of TXA cannot be adequately defined. Evidence supporting the routine use of TXA in paediatric cardiac surgery remains weak. © The Author 2012. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.