Venous thromboembolism is a major medical and social economic problem. In most cases thrombosis occurs in deep veins of low extremities or as pulmonary embolism, the other parts (upper extremities, CNS, abdominal) are affected less often. A major progress in the knowledge of etiopathogenesis of this disease has been made, especially in genetic predisposition. In the article we discuss current knowledge of inherited thrombophilia, the indication to laboratory examination. However, the knowledge of acquired risk factors for venous thrombosis is very important as well. Venous thromboembolism is a multifactorial disease and it is also a big challenge for physicians, because thromboprophylaxis can be prevented by correct preventive measures.