Venous insufficiency can be defined as a fixed venous outflow disturbance of the limbs. It is caused by the malfunction of the venous system, that may or may not be associated with venous valvular insufficiency, and may involve the superficial or deep venous system of the lower limbs, or both. The CEAP scale includes clinical, etiologic, anatomic and pathophysiologic aspects and has been used in the assessment of venous insufficiency. Clinical classification comprises of 7 groups. It takes into account the appearance of the skin of the lower limbs, presence of edema, teleangiectasis and varicose ulcers. Clinical grading: Group C0 - no visible changes in the clinical examination; Group C1 - telangiectasis, reticular veins, redness of the skin around the ankles; Group C2 - varicose veins, Group C3 - the presence of edema without skin changes; Group C4 - lesions dependent of venous diseases (discoloration, blemishes, lipodermatosclerosis); C5 Group - skin changes described above with signs of healed venous ulcers; Group C6 - skin lesions such as in groups C1 to C4 plus active venous ulcers. Etiological classification includes: Ec – congenital defects of the venous system, Ep – primary, pathological changes of the venous system, without identification of their causes; Es - secondary causes of venous insufficiency of known etiology (post-thrombotic, post- traumatic, etc.). There are many methods of assessing the venous system. One of the most accurate methods is an ascending phlebography, which is especially useful in determining detailed anatomy of the venous system, venous patency and identification of perforans veins . The second method may be a descending phlebography, useful in determining the venous reflux and morphology of venous valves. Another radiological method is varicography, in which the injection of the contrast medium directly into the veins is performed. It is especially useful in the „mapping” of venous connections. Trans-uterine phlebography, when contrast medium is injected into the bottom of the uterus and its flow is observed, is a very rare test. A similar method is used in a selective phlebography of the ovarian vein and internal iliac vein. This examination is performed when there is a suspicion of connections between varicose veins of the inferior extremities and the pelvis, in case of the occluded iliac and femoral veins. However, these tests are highly invasive, causing a lot of discomfort and are connected with numerous complications, particularly the development of venous thromboembolism. An invasive study, but not exposing to the emission of ionizing radiation, is a measurement of the marching pressure (known also as ambulatory venous pressure - AVP). Ultrasound Doppler is the „gold standard” in the diagnosis of venous system. Color Doppler technique is irreplaceable due to its non-invasiveness, availability, constantly improving of the ultrasound machines and is the method of choice in pregnancy. Unfortunately, clinical correlation of Doppler ultrasound and thrombosis is bad. Invasive methods, which include various types of phlebographies, have been reserved only for cases of very high diagnostic doubt.