Most hospitalized patients present risk factors for venous thromboembolism (VTE). Deep vein thrombosis and pulmonary embolism are relevant causes for morbidity and mortality in the perihospital phase, with a possibly fatal outcome. Surgical as well as nonsurgical patients with acute medical illness are at risk and show comparatively high rates of VTE. Because of this, an effective and safe prophylaxis for hospitalized patients is necessary. Definition of different risk categories and treatment of patients according to the individual risk profile is standard in VTE prophylaxis. For VTE prophylaxis various medical and mechanical options are available.