Background The causal relationship of clinically-significant atrioventricular block (AVB) and coronary artery disease (CAD) is uncertain. Objectives We investigated whether CAD is related to irreversible AVB requiring permanent pacemaker. Methods and Results Total 188 consecutive patients with new-onset AVB requiring pacemaker were evaluated. All patients underwent invasive or noninvasive coronary evaluation. Irreversible AVB was observed in 173 patients (92.0%) who underwent implantation of permanent pacemaker (IB group) and reversible AVB was observed in 15 patients (8.0%, RB group). In IB group, significant CAD was observed in 46 patients (26.6%) and there were no patients with acute myocardial infarction (AMI). In RB group, 14 patients (93.3%) had CAD (P<0.001) and 13 patients (86.7%) presented with AMI (P<0.001). On the aspect of CAD type and reversibility of AVB, 13/13 (100%) patients of AMI, 0/2 (0%) of unstable angina, and 1/43 (2.3%) of stable angina had reversible AVB. Conclusions AVB in patients with CAD other than AMI may be irreversible. These results suggest that coronary evaluation is not a mandatory procedure for all patients with AVB to assess reversibility of AVB prior to pacemaker implantation. Keywords : atrioventricular block; coronary artery disease; pacemaker.