We present a review of 131 cases in which blood was retrieved and reinfused using Constavac Blood Conservation blood retrieval and reinfusion device postoperatively. The total number of cases in this study included 84 THA, 19 Rev. THA, 16 unilateral TKA and 12 bilateral TKA. The examinations of hemoglobin, hematocrit, antithrombin III, fibrinogen and D-dimer were initiated prospectively before surgery in each case. These parameters were also examined at postoperative day 1 and at day 7 for the evaluation of safety of Constavace Blood Conservation system. The aerobic and anaerobic bacterial culture tests of draining blood were also taken. The results were as follows: 1. The amount of total blood lost averaged 1264±466cc in THA, 2187±632cc in Rev. THA, 1651±543cc in unilateral TKA and 3445±1532cc in bilateral TKA. 2. The amount of blood retrieved and transfused averaged 499±227cc(39% of total lost blood) in THA, 578±527cc(26%) in Rev. THA. 953±451cc(58%) in unilateral TKA and 2219±1191cc(64%) in bilateral TKA. The amount of reinfusion averaged 71% of blood retrieved in THA, 62% in Rev. THA, 80% in unilateral TKA and 84% in bilateral TKA. 3. Fifty one cases out of 84 cases in THA and 14 case out of 28 cases in TKA underwent operation without homologous blood replacement. In the remaining cases, transfused banked blood averaged 364cc(29% of total lost blood) in THA, 620cc(27%) in Rev. THA, 485cc(29%) in unilateral TKA and 914cc(26%) in bilateral TKA. 4. There were no significant change in hemoglobin and hematocrit at postoperative day 7 compared with the preoperative state. 5. The antithrombin III, fibrinogen and D-dimer were converted to normal range at postoperative day 7. 6. The aerobic and anaerobic bacterial culture tests of reinfusing blood proved to be negative in all cases.