Acute pulmonary thromboembolism is a complication of deep venous thrombosis. The incidence of pulmonary embolism increases with age and is higher in persons with risk factors for deep venous thrombosis. The clinical presentation includes dyspnoea, frequently also chest pain, and in some patients syncope. The diagnosis of pulmonary embolism has two steps: if pulmonary embolism is suspected, the probability of pulmonary embolism is assessed; if the probability is high, then the diagnosis is confirmed or rejected by diagnostic imaging. The treatment of patients with confirmed pulmonary embolism depends on the prognosis. Patients with high risk pulmonary embolism are treated with thrombolysis, or with catheter or surgical embolectomy if contraindications for thrombolysis are present. In low risk pulmonary embolism, the prevention of deep venous thrombosis is achieved with anticoagulation only. Late recurrences of pulmonary embolism are prevented with continuous anticoagulation. Anticoagulation is prescribed for at least 3 months, and it may be lifelong, depending on the risk of recurrence of deep venous thrombosis and the risk of bleeding complications.