PURPOSE: To analyse Doppler findings in patients with chronic venous insufficiency, and evaluate the usefulness of color Doppler ultrasonography. MATERIALS AND METHODS: Thirty-seven limbs in 29 patients were evaluated with color Doppler ultrasound for suspected chronic venous insufficiency. To determine luminal patency and valvular competence, the venous system was examined; more than 1 sec of reflux flow during Valsalva maneuver and after release of distal compression in the popliteal vein indicated incompetence. RESULTS: Venous insufficiency was seen in 30 cases (81%), and was Superficial in 14 (38%), deep in eight (21.5%), and combined in eight (21.5%). In seven limbs (19%), veins were normal. Six cases of insufficiency, four of which were deep, were combined with deep venous thrombosis. CONCLUSION: In cases of chronic venous insufficiency, color Doppler ultrasound is useful for defining the exact site of venous incompetence and evaluating venous luminal patency.