Pulmonary embolism (PE) is a frequent pathology, the mortality of which remains elevated despite the efficacy of anticoagulation. This is mainly due to diagnostic difficulty, resulting from the low sensibility and specificity of clinical signs and routine exams in PE. The best diagnostic approach relies on decision making algorithms based on the determination of a clinical probability, which in turn dictates the choice of specialized exams (C-scan/scintigraphy, venous duplex, angiography and D-dimers). Risk stratification, which is based on the presence of hemodynamic alterations (right ventricular dysfunction, shock) is essential to guide therapy. In case of shock (massive embolism), treatment relies on systemic thrombolysis. In the presence of right ventricular dysfunction without shock (sub-massive embolism), the advantage of thrombolysis over anticoagulation alone has not been clearly demonstrated. In all other cases, as long as no contraindication exists, therapeutic anticoagulation with heparin must be initiated as soon as PE is suspected, since the mortality of this condition is highest in the two first hours following presentation.