A prospective analysis of perioperative red blood cell transfusion practice in 110 patients undergoing elective primary total hip arthroplasty was conducted as a part of a quality assessment programme at the National Orthopaedic Hospital. In addition to demographic and clinical data, blood loss and perioperative transfusions were also recorded. Blood was collected for evaluation of haematocrit levels at predetermined intervals (preoperative and 6 h, 1, 2, 3, 7 days, postoperatively). Blood transfused with the patient's haematocrit of more than 30 per cent was considered inappropriate. In addition, a discharge haematocrit exceeding 36 per cent was chosen to identify overtransfusion. Eighty-four per cent were transfused a total of 191 units of homologous blood. Only 4 units were transfused between 3 patients, intraoperatively. All intraoperative transfusions were appropriate. Using the preset criteria (i.e. blood transfused with haematocrit of more than 30 per cent), 36 per cent of total units transfused were inappropriate. Using the criterion of discharge haematocrit of more than 36 per cent, 24 per cent of the patients were overtransfused. As compared to a previous retrospective analysis of blood transfusion in the same patient population which showed that inappropriate transfusion occurred in 45 per cent of the patients, the results from this study suggest a trend towards a more conservative transfusion practice. The improvement in transfusion practice may be due to the ongoing quality assurance programme and the use of transfusion guidelines.