Twenty three patients suffering from severe chronic ischemia of the lower limbs were explored by conventional and digital angiography. A comparative study of these 2 angiographic techniques was carried out to appreciate the pre-operative distal vascular tree and the surgical indications. In all cases, digital angiography was never found to be less informative than conventional angiography. In 14 cases, the surgical approach was changed as a result of digital angiography in 4 cases the method of revascularization and in 10 cases the surgical indication itself (distal bypass instead of amputation). The authors consider digital angiography to be essential in this surgical indication.