Objectives. We sought to ascertain the long-term fate of saphenous vein grafts known to be angiographically normal or minimally diseased 5 years after operation. This information may prove helpful in the management of such grafts at reoperation. Background. Patients undergoing a second coronary bypass operation frequently have one or more saphenous vein grafts that remain widely patent. It is common practice during such reoperations to replace atl vein grafts that are older than 5 years, including those with little or no angiographic stenosis, because of the risk of late vein graft closure. However, the long-term behavior of these angiographically normal or minimally diseased vein grafts has not been well elucidated. Methods. Sixty-two patients with a total of 131 angiographically normal or minimally diseased (<35% diameter narrowing) vein graft segments studied 6.1 +/- 2.1 years (mean +/- SD) after coronary bypass operation were identified by reviewing the cardiac catheterization records of the Veterans Affairs Medical Center, Buffalo, New York. Repeat angiography was performed on these patients 5.1 +/- 1.4 years after the initial post-operative angiogram (11.0 +/- 2.0 years after operation). Results. On restudy, 53% of the vein grafts remained normal or only minimally diseased, 18% showed moderate stenosis (35% to 69%), 8% were patent but with severe disease (70% to 99%) and 21 % were totally occluded. Disease progression was similar in grafts that were previously normal compared with those that had minimal disease. Conclusions. The long-term patency of angiographically normal or minimally diseased vein grafts is good (79% 5-year patency rate, 71% free of severe disease). The presence of minimal disease does not adversely affect long-term patency. The recommendation to replace normal or minimally diseased vein grafts during late reoperation should be reevaluated.