100 patients scheduled for total knee arthroplasty were randomized to either receive or not receive intraoperative intraarticular administration of a thrombin-based hemostatic agent. The purpose of this study was to determine the efficacy of the thrombin-based hemostatic agent (Floseal, Baxter) on reducing blood loss following total knee arthroplasty. Drain output, hemoglobin (Hb) and hematocrit levels, estimated red blood cell loss, and transfusion were assessed during the first 3 days postoperatively. The thrombin-based hemostatic agent group demonstrated significantly lower blood drainage in the first 24h after surgery, and displayed a significantly reduced transfusion rate, though Hb and estimated total red blood cell loss were not observed to significantly differ between groups.