The method of occlusive plethysmography giving an exact quantitative assessment of resistance of the venous bed was used for the examination of 91 patients with different degrees of alterations of the venous outflow before and after surgery. An analysis of the data obtained has shown the efficiency of the method as allowing to supplement and sometimes to substitute invasive methods of examination especially for the assessment of the venous outflow in profound veins and of effects of the surgical treatment.