Reconstructive surgery in chronic venous obstruction of the lower limbs. Forty-one patients with chronic venous insufficiency due to venous trunk obstruction of the lower limbs underwent 43 flow reconstruction procedures consisting of either free veno-venous bypass or venous transposition. The indicating symptoms for these procedures were (1) progressive chronic edema, (2) claudication while walking, or (3) trophic lesions. Doppler ultrasound and plethysmographic techniques were employed in the diagnosis while phlebography was considered the most useful and most essential technique. Iliac vein obstruction was the most common venous obstruction, followed by superficial femoral vein obstruction. Two patients were operated on for combined obstruction at both levels. Free veno-venous bypass was the most frequently used procedure. In two cases of cavo-iliac obstruction, an original technique of femoro-axillary veno-venous bypass yielded good results. Temporary arteriovenous fistulas to improve patency at sites distal to venous bypass were used in the most complex cases. Good results were obtained in 80% of the operated cases. Postoperative follow-up phlebograms were obtained in 30 of 43 operations. 