Purpose The performance characteristics and clinical outcome of a novel hemoconcentrator, the HemoSep (Brightwake, Nottingham, United Kingdom), for reusing salvaged blood postoperatively were evaluated. Description HemoSep concentrates blood by removing the fluid component from a pooled volume of blood salvaged at the end of the operation from the heart-lung machine. During a 6-month period, 102 patients were prospectively randomized into two groups. In group 1 (n = 52), salvaged blood in the venous reservoir after the cessation of cardiopulmonary bypass was reused by the HemoSep device and the processed blood was retransfused to the patients. In group 2 (n = 50), the control group, the operation proceeded using conventional method without using the hemoconcentrator. Evaluation The mean amount of processed blood was 775 ± 125 mL. The efficacy of the HemoSep device was confirmed by the percentage concentration of the hematocrit at 15 and 40 minutes. Serum albumin and factor VII levels were concentrated more than threefold at 40 minutes vs baseline measurements. Patients who received processed blood had significantly less need for an allogeneic transfusion. Conclusions The HemoSep device functions as designed and without technical failures, offering a complementary technique in blood management during cardiac operations.