Complete heart block and other cardiac conduction defects are recognized problems that occur during the early postoperative phase after aortic valve replacement (AVR). However, little is known about conduction defects that occur months and years after surgery. A total of 100 consecutive patients was followed prospectively for a mean of 73 months after AVR. Late conduction defects occurred in 13.7% of operative survivors who had normal preoperative and perioperative ECGs. One patient required pacemaker implantation 82 months after AVR. The incidence of late conduction defects appears to be 15- to 30-fold higher compared with randomly selected normal populations. This high incidence, though not often resulting in complete heart block or need for definitive pacing, calls for regular follow up with precise evaluation of ECGs and arrhythmias, even years after AVR.