In spite of widely applied prophylaxis against thrombo-embolic venous disease its future complications still present important clinical issue. According to rough statistics this disease occurs in 71/100 000 persons per year and reveals in 1/3 as pulmonary embolism and in 2/3 as a pure thrombotic venous disease. Massive pulmonary embolism is at present a major cause of death in hospitalized subjects. In the USA mortality due to diagnosed pulmonary embolism is reported as approximately 25 000 cases per year. The aim of this paper is to draw attention to the asymptomatic cases of the thrombotic venous disease in the patients before hip arthroplasty. A retrospective clinical analysis of 210 total hip replacements (years 2005-2008) was performed. Standard perioperative routine antithrombotic prophylaxis with low-molecule heparins was introduced in each case. Special attention was paid to the occurrence of the risk factors or the presence of venous thrombosis in the lower extremities perioperatively. In the analyzed group preoperative ultrasound revealed in 5 (2.38%) cases asymptomatic venous thrombi reaching above the knee region and this was the cause of postponing of the procedure. In the early postoperative period pulmonary embolism was evidenced in 4 cases (1.9%). The authors suggested that preoperative ultrasound investigation of lower extremities venous system is important issue together with the assessment of d-dimers in the blood in all patients admitted to total hip arthroplasty. In any suspicion of the pulmonary embolism in these patients an angio-CT should be performed as an emergency.