For the majority of patients with pulmonary embolism the recommended therapy consists of a 5 to 7 day treatment with heparin followed by a treatment with oral anticoagulants given for at least 3 months. The currently recommended duration of oral anticoagulant treatment for pulmonary embolism is the result of the balance between the benefit provided by treatment, essentially the prevention of recurrence, and the bleeding risk and inconvenience associated with treatment. Risk of bleeding and inconvenience should be assessed on an individual base. Concerning the risk of recurrence, patients with pulmonary embolism can be classified in three groups: patients with pulmonary embolism associated with temporary risk factors, patients with pulmonary embolism associated with persistent risk factors, patients with pulmonary embolism occurring in the absence of any identifiable temporary or persistent risk factors for venous thromboembolism (idiopathic or unprovoked pulmonary embolism). Due to the limitations of the currently available oral anticoagulant agents, search for the optimal agent to be used in the long-term treatment of pulmonary embolism is still open.