During a 36-month period 74 patients underwent infrainguinal in situ saphenous vein bypass to the popliteal or tibial vessels. The first 54 operations were performed with standard valvulotomes and valve-cutting scissors, while in the last 20 operations a new intraluminal valve-cutting device was used to incise the valves. Ninety-four percent of bypasses were performed for limb salvage, 80% of all operations were done to the tibial vessels, and 31% of bypasses were done to the ankle vessels. The operation was attempted in 81 patients and completed in 74 patients, for a vein utilization rate of 91%. Fifty-five percent of all veins had a distal diameter of less than 4 mm (average 3.6 mm). The patency rates were 92% at 3 months and 90% at 12 and 36 months for all grafts. There were six failed grafts, all within the first 6 months, and eight diabetic patients required reoperation, two for missed valve leaflets, and three needed revision of the distal anastomosis; however, all these grafts were patent at the time of reexploration. There were four perioperative deaths and two patients had nonfatal postoperative myocardial infarctions. This study demonstrates that in situ saphenous vein grafting provides for a high vein utilization rate and suggests that the technique provides for higher graft patency and limb salvage rates than do more traditional types of procedures.