A total of two hundred and twenty-eight 18-to-83-year-old patients diagnosed with thrombotic occlusion of the lower-limb deep veins were examined in order to evaluate the possibilities of colour duplex angioscanning as a method aimed at monitoring both the course of and efficacy of treatment for acute venous thrombosis, as well as at preventing thromboembolic complications. Studied were the localization, incidence rate, and complications of the course of various types of venous thrombosis. It was demonstrated that an uncomplicated course the disease was observed in more than 80% of cases. At the same time, using dynamic ultrasonic monitoring made it possible to promptly detect progression of the pathological process in 3.5% of cases, and to introduce due amendments in the treatment policy being carried out. Also shown were the possibilities of the colour duplex scanning (CDS) technique in assessing the outcomes of the endovascular prevention of pulmonary thromboembolism (PTE) by means of implantation of the cava filter. The CDS turned out efficient in diagnosing the development of such complications as dislocation of the cava-filter and thrombus formation in the area of the cava filter. It was determined that the terms of fixation of the embolus-hazardous (floating) thrombus varied from 6 days to 6 months, which is of great importance in selecting the optimal period for temporary endovascular prevention of PTE.