The objective of this study was to compare the treatment plan designed on the basis of preoperative duplex scanning evaluation of the critical limb ischemia with the treatment plan finally carried out, after assessing the findings obtained during surgical or endovascular treatment. Over a period of 51 months a preoperative duplex scanning study was carried out in 335 consecutive patients with chronic critical ischemia, to design the best therapeutic strategy. Agreement between both plans were as follows: 80%, 82,7% and 59% in the examinations of the iliac arteries, femoropopliteal or tibial arteries respectively. The operation plan was more frequently modified due to a duplex scanning failure in procedures involving the the distal vessels(10 of 44 [22.7%], p < 0.01). In conclusion, duplex scanning evaluation of patients with occlusive arterial disease of the lower limbs permits the design of both a medical and a surgical or endovascular treatment plan with a high level of agreement with the findings obtained during the revascularization procedure.