The diagnosis of pulmonary embolism (PE) remains a considerable challenge to any physician. Irrespective of the diagnostic progress, the prevalence of fatal PE in autopsy studies is still about one third. Introducing sufficient anticoagulant therapy, mortality due to PE can be decreased from about 30% to 2-8%. Therefore, immediate anticoagulant therapy should be given, if PE is clinically suspected. Initial anticoagulation by low-molecular-weight heparins is as effective as unfractionated heparin in non-massive PE. In patients suffering from massive PE, thrombolytic treatment is indicated. Whether patients with submassive PE and/or elevated cardial troponins should also receive thrombolytic treatment, is still under debate. After PE has been established, vitamin-k-antagonists are the current standard of secondary prophylaxis.