Purpose:To analyse Doppler findings in patients with chronic venous insufficiency, and evaluate the usefulness of color Doppler ultrasonography. Material 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 1sec 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%). Inseven 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 incompletence and evaluating venous luminal patency.