ABSTRACT: Background Although several risk schemes have been proposed to predict new-onset atrial fibrillation (AF), clinical prediction models specific for Asian patients were limited. In the present study, we aimed to develop a clinical risk score (Taiwan AF score) for AF prediction using the whole Taiwan population database with a long-term follow-up. Methods and Results Among 7 220 654 individuals aged ≥40 years without a past history of cardiac arrhythmia identified from the Taiwan Health Insurance Research Database, 438 930 incident AFs occurred after a 16-year follow-up. Clinical risk factors of AF were identified using Cox regression analysis and then combined into a clinical risk score (Taiwan AF score). The Taiwan AF score included age, male sex, and important comorbidities (hypertension, heart failure, coronary artery disease, end-stage renal disease, and alcoholism) and ranged from -2 to 15. The area under the receiver operating characteristic curve of the Taiwan AF scores in the predictions of AF are 0.857 for the 1-year follow-up, 0.825 for the 5-year follow-up, 0.797 for the 10-year follow-up, and 0.756 for the 16-year follow-up. The annual risks of incident AF were 0.21%/year, 1.31%/year, and 3.37%/year for the low-risk (score -2 to 3), intermediate-risk (score 4 to 9), and high-risk (score ≥10) groups, respectively. Compared with low-risk patients, the hazard ratios of incident AF were 5.78 (95% CI, 3.76-7.75) for the intermediate-risk group and 8.94 (95% CI, 6.47-10.80) for the high-risk group. Conclusions We developed a clinical AF prediction model, the Taiwan AF score, among a large-scale Asian cohort. The new score could help physicians to identify Asian patients at high risk of AF in whom more aggressive and frequent detections and screenings may be considered.