Large vessel involvement by skeletal and soft tissue sarcomas of the extremities does not change the modern limb sparing surgery for those neoplasms. An arterial and, if the vein is open, a venous bypass should always be offered to any patient young or old, with high or low grade sarcoma, because preserving the limb permits quicker rehabilitation, which is particularly useful in the case of a short life expectancy. In 650 cases of skeletal sarcomas, 10 arterial (1.5%) and four venous bypasses were done, all with autologous veins but one in PTFE; we had no problems except a silent arterial occlusion. Of 1000 patients with soft tissue sarcomas, 32 (3%) had vessel involvement permitting limb sparing surgery. The arterial bypass, which is the limb-saving operation, was performed 16 times with a PTFE with one early occlusion and four cases of prosthesis infection, with two amputations despite redo operation with an autologous vein. The more recent 16 cases were, therefore, always done with biological vessel substitution--autologous vein or tissue bank vessel--with only one infection that healed without operation and one case of homograft rupture followed by amputation. Since 1999 in all 13 resected cases with an open vein, we did the arterial and the venous bypass (twice PTFE, six autologous vein, and five bank vessel) with the aim of avoiding postoperative venous hypertension, but only four of the venous bypasses remained open. Venous bypasses are a harmless, but still experimental, procedure.