Four hundred thirteen cemented total hip arthroplasties and 852 cemented total knee arthroplasties were evaluated prospectively for postoperative pulmonary embolism. Inclusion criteria were a diagnosis of osteoarthritis, age 50 to 75 years old, cemented primary arthroplasty, and prophylaxis with low-dose warfarin (Coumadin, DuPont Pharma, Wilmington, Delaware). All patients underwent a preoperative perfusion scan and postoperative ventilation perfusion scan with all moderate probability scans evaluated with arteriogram. The overall incidence of pulmonary embolism was 3.8% after cemented total hip arthroplasty and 5.6% after cemented total knee arthroplasty. Because of a weight bias, patient age, weight, and gender-matched comparison was performed. Two hundred eighty-two patients from each group were matched with identical age, weight, and gender. The incidence of postoperative pulmonary embolism was 4.3% for total hip arthroplasty and 4.6% for total knee arthroplasty. These results do not support the contention that pulmonary embolism is higher after total hip arthroplasty than after total knee arthroplasty.