We evaluated whether an increased carotid intima-media thickness (cIMT) and brachial artery IMT (bIMT) are related to diffuse coronary involvement rather than focal lesions. Patients (n = 88) with at least 1 significant lesion of the main epicardial coronary arteries (50%) were included in the present study. We used a novel score based on length and mean narrowing of all lesions in order to predict diffuse coronary involvement. Both cIMT and bIMT were higher in patients with long coronary lesion than focal lesion (P < .001). The patients with long coronary lesion had a higher rate of total coronary involvement than patients with focal lesion (P < .001). The cIMT had a higher correlation with total atherosclerotic burden in the coronary vasculature (r = .495, P < .001) and the longest lesion length (r = .489, P < .001) than cardiovascular risk factor score (r = .453, P < .001 and r = .324, P = .012, respectively). These findings may be valuable for clarifying the prognostic value of IMT measurements.