BACKGROUND AND OBJECTIVES: Atrial fibrillation (AF) is the most common significant arrhythmia in the general population, and it is associated with increased cardiovascular morbidity and mortality. The incidence of and the risk factors for new-onset AF have not been well evaluated in Koreans. SUBJECTS AND METHODS: We retrospectively analyzed 16,568 adults (median age 49 years, 10,685 males and 5,883 females) who had repeatedly received screening tests for general health at the Health Promotion Center, Samsung Medical Center in Korea between March, 2001 and June, 2006 (mean follow up duration: 44 months). RESULTS: Sixty one cases had new-onset AF noted on the electrocardiogram (ECG). On the univariate analysis, age, male gender, a history of coronary artery disease and taking hypertension medication, the waist circumference, body mass index, fasting glucose, hemoglobin A1c, fibrinogen, and left atrium enlargement seen on ECG at baseline were significantly associated with new-onset AF. After multivariable adjustment, the independent risk factors for predicting new-onset AF were male gender [odds ratio (OR): 3.356, 95% confidence interval (CI): 1.168-9.643, p=0.025] and a history of coronary artery disease (OR: 4.657, 95% CI: 1.703-12.737, p=0.003). CONCLUSION: The risk factors for predicting new-onset AF in persons who received general health screening tests were male gender and a history of coronary artery disease.