A study was conducted applying a technique of venous impedance plethysmography for the quantitation of venous reflux to a group of 20 normal persons and five patients with postphlebitic limbs. Results demonstrate a significantly higher reflux refilling rate for those patients with postphlebitic limbs compared with the refilling rate for those in the normal group. It is believed that this technique is a valuable diagnostic tool for detecting venous reflux caused by valve incompetence and that it provides an indication of progression of venous insufficiency in the patient.