Background: Atrial fibrillation (AF) increases heart failure (HF) risk and can eventually increase morbidity and mortality. Therefore, recognizing risk factors in AF patients is crucial to prevent heart failure. To date, there has been no research on this topic in Indonesia. Objective: To determine risk factors of new-onset HF in AF patients. Methods: Case–control study was undertaken at Cipto Mangunkusumo Hospital using medical record data from January 2018 to May 2023. AF patients aged ≥18 years with new-onset HF were included in the case group, and AF patients of similar age without HF were included in the control group. Patients with moderate or severe valvular heart disease, congenital heart disease, pacemakers, or implantable cardioverter defibrillators (ICD), or incomplete data were excluded. Logistic regression was used to identify significant risk factors for new-onset HF in AF patients. Results: A total of 132 subjects consisting of 44 cases and 88 controls were included. Bivariate analysis revealed that the significant risk factors for new-onset HF in AF patients were CAD [p =.037; OR 2.34 (95% CI 1.11–4.93)], CKD [p =.000; OR 7.78 (95% CI 3.45–17.53)], and LAVI [p =.002; OR 3.23 (95% CI 1.52–6.85)]. In multivariate analysis, CKD [p =.000; OR 6.31 (95% CI 2.69–14.77)] and LAVI [p =.000; OR 3.49 (95% CI 1.42–9.97)] retained their statistical significance as risk factors of new-onset HF in AF patients. Conclusions: CKD and increased LAVI may increase the likelihood of new-onset HF in AF patients, while hypertension, diabetes, CAD, smoking, and obesity were not significant risk factors for new-onset HF in our study. © 2025 The Author(s). Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.