Noninvasive diagnosis of chronic diseases of the lower limb venous system is an urgent problem of modern phlebology. Ultrasonic examination (USE) makes it possible to judge adequately the condition of the deep and surface veins and, consequently, to improve significantly the management of varicose and post-thrombophlebitic diseases. The authors elaborated an original method for the diagnosis and appraisal of the condition of the lower limb venous system by means of ultrasonic scanning and various functional tests for determining the character of affection of the venous valvular apparatus. Examination of more than 200 patients with primary varicosities and post-thrombophlebitic disease, the use of highly-resolving ultrasonic equipment, and comparison of the results of USE with the findings of radiocontrast phlebography (agreement in 99.8% of cases) allow the conclusion that noninvasive ultrasonic methods must be used widely in appraising the venous status in patients with chronic diseases of the venous system of the lower limbs.