With a greater understanding of the prevention of thromboembolic complications, the incidence of fatal pulmonary embolism after total joint arthroplasty has declined. Although much of our knowledge is centered around deep vein thrombosis and its use as a marker for thromboembolic complications, little is known about the natural history of both symptomatic and asymptomatic pulmonary embolism. Although differing methods of prophylaxis have shown some success, the ideal agent has yet to be discovered. The use of serial lung scanning has shown great use in the diagnosis of pulmonary embolism. Additional studies using effective diagnostic tools are needed to evaluate the risk of recurrent embolism. Only then can the duration of treatment and prophylaxis be determined. Despite the many unanswered questions, the following conclusions can be drawn: (1) fatal pulmonary emboli are a preventable complication of total joint arthroplasty; (2) fatal emboli are often preceded by small and frequently asymptomatic emboli; (3) detection and appropriate therapeutic measures for asymptomatic emboli are possible with the use of serial lung scans and judicious use of pulmonary angiography; and (4) low-dose coumadin has proven to be the most effective agent in lowering the risk of asymptomatic, symptomatic, and fatal pulmonary emboli.