Purpose. To review records of 371 patients who underwent total hip or knee arthroplasty (THA or TKA) with intra-operative blood salvage to determine the allogeneic blood transfusion rate and the predictors for allogeneic blood transfusion. Methods. Records of 155 male and 216 female consecutive patients aged 17 to 95 (mean, 70) years who underwent primary THA or TKA by a single surgeon with the use of intra-operative blood salvage were reviewed. Results. The preoperative haemoglobin level was <120 g/dl in 15% of THA patients and 5% of TKA patients; the allogeneic transfusion rate was 24% in THA patients and 12% in TKA patients. Despite routine use of intra-operative blood salvage, only 59% of THA patients and 63% of TKA patients actually received salvaged blood, as a minimum of 200 ml blood loss was required to activate blood salvage. In multivariable analysis, predictors for allogeneic blood transfusion were female gender (adjusted odds ratio [OR]=2.8, p=0.02), age >75 years (adjusted OR=5.9, p<0.001), and preoperative haemoglobin level <120 g/l (adjusted OR=30.1, p<0.001), despite the use of intra-operative blood salvage. Patients who received allogeneic blood transfusion had a longer hospital stay and greater complication rate. Conclusion. Intra-operative blood salvage is not effective in preventing allogeneic blood transfusion in patients with a preoperative haemoglobin level <120 g/l. It should be combined with preoperative optimisation of the haemoglobin level or use of tranexamic acid.