Pulmonary embolism is a potentially life-threatening disease with occlusion of the pulmonary arteries. The symptoms are manifold and can range from clinically asymptomatic courses to thoracic pain, cough, and dyspnea to shock and cardiovascular arrest. Risk factors for the development of thrombosis and thus also pulmonary embolism are Virchow’s triad hypercoagulability, stasis, and endothelial damage. The diagnosis consists of the clinical pretest probability as well as laboratory diagnostic and imaging procedures. As soon as a pulmonary embolism has been diagnosed, the therapeutic regime must be determined according to risk stratification and can range from outpatient treatment in low-risk cases to acute recanalization in high-risk situations. As a long-term consequence and complication, some patients can develop chronic thromboembolic pulmonary hypertension with the formation of a chronic cor pulmonale.