This retrospective study evaluated the safety and efficacy of post-operative blood salvage and retransfusion in 430 patients undergoing total hip arthroplasty and 530 patients undergoing total knee arthroplasty. Volumes of autologous blood retransfused (mean +/- SD) were 525 +/- 75 and 660 +/- 95 ml in the hip and knee replacement groups, respectively. Overall, 230 patients (24%) also required allogeneic blood transfusion. In a subgroup of 150 randomly selected patients, the values of free haemoglobin in the allogeneic, autologous and patients' blood at the time of surgery were 0.568 +/- 0.112, 0.272 +/- 0.067 and 0.032 +/- 0.011 g/l, respectively. On the first and third post-operative days, the levels in patients' blood were 0.092 +/- 0.039 and 0.057 +/- 0.028 g/l, respectively. There were no major complications; transient chills and fever were reported in 99 (10.3%) and 115 patients (12.0%), respectively. In conclusion, post-operative blood salvage and retransfusion is a safe way to reduce the need for allogeneic blood transfusion in patients undergoing elective orthopaedic surgery.