Between 1987 and 1991, 209 patients were operated by the Ilizarov method in the Department of Orthopaedic and Traumatologic Surgery of the University of São Paulo Medical School. Five of them presented vascular complications during the treatment. All were adults treated for long bone pseudarthrosis. The vascular lesion occurred in the femoral superficial artery (one case), in the popliteal artery (one case), and in the posterior tibial artery (one case); in the remaining two patients it was not possible to determine the exact site of the lesion. The clinical manifestation of the vascular problem was bleeding at the cutaneous point of the Kirschner transfixation wires. Arteriography was done in all cases but its interpretation was difficult because of the presence of the external fixator. The treatment of the vascular complications was following: in the case of injury in the femoral artery, the external fixator was taken off and a by-pass with an inverted graft of the saphenous vein was made the same procedure was done in the popliteal artery but in this case it was not necessary to remove the external fixator; the remaining case with the lesion in the posterior tibial artery was treated by ligature. In two cases where the artery involved was not determined--one in the upper extremity with the external fixator applied to the femur--the bleeding stopped after the removal of wires.