Pulmonary embolism (PE) and venous thromboembolism are two clinical manifestations of a single entity - venous thromboembolism. PE usually occurs through due thrombi from the lower veins, and in 10-15% of cases are due thrombus from upper veins or right heart failure. Significance is mainly determined by the frequency (1/1000 per year in the adult population; less in younger but significant increase with increasing age), the risk of mortality is important in acute and chronic diseases that are associated with this clinical manifestation. Acute pulmonary embolism is often fatal, with a mean annual mortality of about 30% in untreated. Many deaths occur because of recurrent PE within the first few hours after the initial event. In the nineteenth century, Virchow the mechanism of thromboembolism categorized into three groups: changes in the blood vessel wall, a reduction of blood flow (path) and changes in the composition of the blood (hypercoagulable, prothrombotic). Modern interpretation of the pathogenesis of thromboembolism, which is processed corresponds Virhovljevom concept. In general thromboembolic events can be a result of complications of individual risk factors as increased thrombotic potential.