The purpose of this prospective study was to evaluate the safety of salvage and reinfusion of postoperative sanguineous wound drainage using the ConstaVac Blood Conservation System (Stryker, Kalamazoo, MI). A prospective analysis of 135 primary total hip and total knee arthroplasties was carried out. The collection time for reinfusion was limited to 6 hours, and suction pressure was kept to a minimum by using the lowest setting on the device. For all patients, no citrate-phosphate-dextrose anticoagulant was added to the reservoir. To evaluate the effect of reinfusion on hemostasis and the blood coagulation system, antithrombin III, fibrinogen, and D-dimer levels of 40 of 135 patients were measured before surgery and on the first and seventh days after the operation. The mean volume of reinfusion of postoperative drainage was 437 mL for the patients with total hip arthroplasties, 883 mt for those with total knee arthroplasties, and 1,713 mt for those with bilateral total knee arthroplasties. Ninety-nine of 135 patients underwent operations without homologous blood replacement. Transient chills with mild fever were seen in 2 patients during reinfusion. No complications related to air embolism, coagulopathy, renal failure, or sepsis were recognized in any of the patients. This study suggests that postoperative blood salvage and reinfusion appear to be safe and effective in patients undergoing primary total hip and knee arthroplasties.