BACKGROUND: Patients undergoing cardiac surgery employing cardiopulmonary bypass frequently require transfusion of homologous blood products and, therefore, are exposed to the risk of transfusions. A administration of autologous platelet-rich plasma may reduce homologous transfusion and attendant risks. This study was designed to investigate the effect of preoperative collection of platelet-rich plasma on the requirement of homologous transfusion and postoperative blood loss in patients undergoing open heart surgery. METHODS: Twenty seven patients undergoing cardiac surgery were divided into control group(n=11) and autologous platelet-rich plasmaphereris(PRP) group(n=16). Autologous platelet-rich plasma was retransfused after offbypass. Hematocrit, platelet count, PT(prothrombin time), PTT(partial thromboplastin time), postoperative blood loss and transfusion requirement were measured. RESULTS: There was no statistical significance between control and PRP group in homologous transfusion and postoperative blood loss. There was no difference in hemoatocrit, platelet count, PT or PTT on immediate post surgery or on day 1. CONCLUSIONS: Autologous platelet-rich plasma did not reduce postoperative blood loss or transfusion reguirements in cardiac surgery.