Background Battery impedance of permanent pacemaker(PMK) was believed to predict the time to replace. The purpose of this study was to evaluate the efficacy of battery impedance in predicting the longevity of PMK. Methods From January 1981 to June 2011, 866 consecutive patients who underwent PMK implantation were enrolled retrospectively. Among total patients, 237 patients underwent replacement of PMK because of elective replacement time or end of life. We retrospectively reviewed the trend of impedance change and estimated the time duration to reach 3,000 Ohms(T3,000Ohm) of battery impedance. And the estimated longevity was compared between different PMK models and types. Results Median age of PMK deployment was 55.8 years old and of PMK replacement 69.2. Diagnosis at presentation was sick sinus syndrome(n=129/54.5%), advanced atrioventricular block (108/45.5%). Composition of PMK mode was VVI(n=94/39.7%), DDD(60/25.3%), VDD(59/24.9%) and AAI(24/10.1%). Median T3,000ohm according to PMK mode was following ; DDD–2514day, AAI–2255day, VDD–2339day and VVI–2160day. Comparisons between PMK models were showed in Figure. Conclusions The time to reach battery impedance of 3,000 Ohms was different between PMK models and types. Although battery impedance could provide useful indicator to estimate battery longevity and time to replace the permanent pacemaker, the difference between PMK models and types should be considered.