Patients with chronic venous insufficiency may have a combination of problems. The veins in the lower extremity can be affected by post phlebitic changes, obstruction, venous valvular incompetence or any mixture of these. Correct medical and/or surgical treatment hinges on the accurate assessment of the venous system. Complete studies of the lower extremity should incorporate ascending and descending venography as well as the clinical presentation. The methods described above easily enable one to achieve this accuracy with a minimal of time and discomfort to the patient. The incidence of primary venous valvular incompetence, may be higher than first anticipated and only by performing descending venography will this cause chronic, venous insufficiency to be unmasked. When employed in the appropriate patient, descending venography is an invaluable asset to diagnosis and ultimate treatment.