Aims: Evaluation of the efficacy of autotransfusion in reducing the need for homologous blood transfusion in total knee arthroplasty. Methods: Prospective randomized study. Patients undergoing total knee arthroplasty were divided in: Group A (72 patients) receiving autotransfusion (Suretrans) and control group B (30 patients) with suction drainage only. Preoperative Hb and demographics of the two groups were comparable. The level of Hb was followed for the first 5 days postoperatively. The amount of homologous blood transfused was also recorded. Results: The average autotransfusion volume in group A was 405±191ml. On the day of the operation and the first postoperative day the Hb in group A was found statistically significantly higher (p< 0.05). On the second and third day the Hb in group B, achieved levels comparable to group A, because patients received homologous blood transfusion. The amount of homologous blood transfused to the patients was significantly higher in group B (average: group A 0.36 ± 0.74u, group B 1.2 ±1u, p< 0.001). Multiple regression analysis suggests that the only factor reducing the need for homologous blood transfusion is the use of the autotransfusion system. Conclusions: there is a statistically significant reduction in the need for blood transfusion by using an autotransfusion system reducing also the possible dangers and complications. Autotransfusion is a simple, safe and cost effective method.