This is a study of 97 patients who underwent 106 femoropopliteal bypass grafts (9 bilateral bypasses) for short-distance claudication and critical ischemia. Patients were divided into 2 groups. The first group (n=64) was followed up by use of duplex scans. The second group (n=42) was followed up in clinic without duplex surveillance. Twenty-three patients from the surveillance group developed stenoses of the grafts. Of these, 14 underwent successful angioplasty. A total of 43 grafts became blocked. Graft occlusion was significantly more common in the nonsurveillance group (n=29) as compared to the surveillance group (n=14) after both 1 and 3 years of observation (p=0.001). Patients with critical ischemia showed a higher rate of graft occlusion than the claudicants (p=0.0075). Sixteen patients in the nonsurveillance group underwent above/below-knee amputation compared to 1 in the surveillance group. There was no significant difference in the mortality rate in the 2 groups. Graft surveillance helped to improve patency of grafts by identifying the correctable lesions.