Ten patients with congenital vein valve aplasia verified at contrast phlebography were evaluated clinically and by physiologic examinations. All had orthostatic edema and varicose veins, but leg ulcers and other "postphlebitic" sequelae were infrequent. Foot volumetry and measurement of ambulatory foot vein pressures revealed a severe deep venous incompetence with a defective muscle pump function and considerable reflux. Eight limbs were operated on with conventional varicose vein surgery and physiologically re-examined six to 26 weeks after the operation. All had an improved ambulatory pressure reduction (p less than 0.001). Foot volumetry revealed better muscle pump function (p less than 0.01), while the reflux flow was unchanged. Surgery of the incompetent superficial venous system is therefore recommended in cases with deep venous insufficiency due to congenital vein valve aplasia.