Background. Atrial fibrillation (AF) is the most common tachyarrhythmia associated with significant cardiovascular morbidity and mortality. Although incidence of AF is known to be growing in the ageing society of Korea, the incidence and the risk factors of new-onset AF have not been well evaluated. Methods. Among 37546 adults who had repeatedly received screening tests for general health at the Health Promotion Center, Samsung Medical Center in Korea between January, 1995 and December, 2010, we retrospectively analyzed 7641 individuals who were older than 60 years and initially in sinus rhythm. Results. During the mean follow up period of 4.2 years, 96 individuals newly developed AF. The incidence rate is 2.99 per 1000 person-years. On the univariate analysis, male gender, history of hypertension, body mass index, waist circumference, blood pressure, left atrial enlargement (LAE) on electrocardiogram, left ventricular hypertrophy and left atrial size in echocardiography, and NT-proBNP level were significantly associated with new-onset AF. After multivariable adjustment, the independent risk factors for predicting new-onset AF were male gender(OR 3.979, 95% CI 1.923-8.234, p<0.001), body mass index (OR 1.150, 95% CI 1.063-1.245, p=0.001), and LAE on electrocardiogram (OR 2.821, 95% CI 1.112-7.153, p=0.029). In 3211 individuals who underwent echocardiography, LA size and E/A ratio were independent predictor for new-onset AF in multivariate analysis. Conclusion. The risk factors for predicting new-onset AF in persons who were older than 60 years and received repeated general health screening tests were male gender, greater body mass index, and LAE on electrocardiogram.