Cockett's syndrome (iliac compression syndrome) results from compression of the common iliac vein by the aortic bifurcation. The anatomical abnormality is frequent (15-20% of the population), but symptoms only appear when compression is pronounced. In a study of 16 patients, predominantly female, the following clinical presentations were observed: venous oedema of the left lower limb in 4 cases; symptoms suggesting iliac phlebitis in 3 cases; pulmonary embolism as first sign of peripheral venous thrombosis in 6 cases; and deterioration of angiodyplasia in 3 cases. In all patients, the diagnosis of Cockett's syndrome was confirmed by cavography. Surgical treatment, successfully performed in 13 patients, consists of uncrossing the artery and vein and placing a clip on the vena cava in case of pulmonary embolism