Long and short PR interval or QT interval are related with cardiovascular outcomes in patients with cardiovascular diseases. This study was aimed to investigate the change and difference of PR interval, an index of atrioventricular conduction time, and QT interval, an index of ventricular depolarization and repolarization time, according to gender and age in healthy people. We analyzed 121,286 electrocardiograms from 60 to less than 100 beats per minute among people performed for health surveillance at Seoul National University Bundang Hospital for the past 10 years. The mean of PRc interval and QTc interval corrected by RR intervals using Bazzett’s formula, were compared according to age and sex. PRc interval was longer in male than female by 11.2 msec (female 170±24 vs male 182±24, P<0.0001) and QTc interval was longer in female than in male by 11.5 msec (female 428±23 vs male 416±23, P<0.0001). There was no significant difference in PR and QT interval between sex and age, sex and gender before puberty. There was a difference between men and women after puberty, and this difference was decreased after menopause (sixth decade). In the case of PR interval, there was a difference in the lengthening of the male after the third decade, and in the case of the QT interval, the lengthening of the female was observed after second decade. PR interval and QT interval have a clear difference between men and women. This suggests that there is a gender difference in the atrioventricular conduction time and ventricular repolarization and depolarization time. Therefore, further study on the gender differences in cardiovascular diseases is warranted.