Consecutive patients (n = 235) with coronary ischemia were studied; 69 patients (29%) had diabetes. An oral glucose tolerance test (OGTT) was administered to the 166 patients without diabetes; 76 (46%) had normal glucose tolerance (group I = NGT), 68 (41%) had impaired glucose tolerance ([IGT] group II = IGT), and 22 (13%) had diabetic glucose tolerance (DGT). The DGT patients were added to the known diabetics forming (Group III; n = 91). Multivessel disease was significantly more prevalent in group III; 30 patients (43%) in group I, 32 patients (51%) in group II, and 57 patients (69%) in group III (P = .002). Gensini scores were 43.20 +/- 24.92 in group I, 54.22 +/- 42.61 in group II, and 60.59 +/- 38.21 in group III. (P = .037) The severity of coronary artery disease is related to abnormal glucose tolerance. Patients with IGT could be neglected in terms of interventions focused to improve risk factors.