Delayed complete atrioventricular (AV) block due to jailed septal branch during percutaneous coronary intervention (PCI) of left anterior descending artery is a rare complication. Here, we present a case of an elderly male who developed episodes of complete AV block and cardiac arrest 2 days after transient occlusion of the septal branch during PCI, and received permanent pacemaker implantation. This case had shown first-degree AV block plus right bundle branch block before PCI, and the presence of these preexisting conduction abnormalities may have been the underlying mechanism by which the transient occlusion of jailed septal branch cause complete AV block.