The reported high incidence of coronary atherosclerosis in many transplant series led us to critically review our experience in 83 patients who have had selective coronary angiography at ≥1 years after transplantation. Angiograms were reviewed for evidence of coronary vascular disease, and quantitative analysis of multiple coronary artery segments was performed in serial films. Qualitative analysis revealed only 3 of 83 patients with any angiographic abnormality at follow-up, 1 with minimal luminal irregularities in the right coronary artery at 1 year, a second with a 50% diameter stenosis of the proximal left anterior descending artery and minimal irregularity of the proximal circumflex artery at 1 year and a third patient who developed a new 30% diameter eccentric proximal right coronary artery stenosis at 3-year follow-up. The cumulative incidence of graft vascular disease assessed angiographically was therefore 2% at 1 year and 4% at 3 years. Quantitative analysis, however, showed a significant decrease in coronary artery luminal diameter over time. The mean left main coronary artery diameter decreased from 5.4 � 0.9 mm at 1 year to 4.7 � 0.8 mm at 3 years (p = 0.0007). A significant reduction in luminal diameter also was found in the following segments (measurements are given 1 vs 3 years): proximal left anterior descending artery (4.4 � 0.7 vs 4.0 � 0.5 mm, p = 0.003), mid-left anterior descending (2.7 � 0.5 vs 2.5 � 0.4 mm, p = 0.009), proximal circumflex (3.9 � 0.6 vs 3.6 � 0.7 mm, p = 0.0003), mid-circumflex (3.0 � 0.6 vs 2.8 � 0.7 mm, p = 0.005) and proximal right coronary artery (4.0 � 0.7 vs 3.7 � 0.6 mm, p = 0.05). In addition, 7 of 8 hearts obtained at autopsy or retransplant showed significant degrees of diffuse fibrointimal hyperplasia, unsuspected from angiography performed as recently as 7 days earlier. Thus, although segmental coronary vascular disease was uncommon in these patients, diffuse vascular disease may be insidious, progressive and undetectable by current angiographic techniques.