Introduction: Atrial remodeling, characterized by changes in atrial structure and function, is central to the development and maintenance of atrial fibrillation (AF). Besides left atrial (LA) remodeling, right atrial (RA) remodeling may also contribute to AF perpetuation, and its presence may affect clinical outcome of AF ablation. Bi-atrial remodeling in patients with AF is rarely assessed and data on the presence of RA fibrosis, the relationship between RA and LA fibrosis, and possible association of RA remodeling with AF recurrence after ablation is limited. Methods: 110 AF patients undergoing initial pulmonary vein isolation (PVI) were included in the present study. Patients were in sinus rhythm during cardiac magnetic resonance (CMR) imaging performed prior to ablation. LA and RA volumes and function (volumetric and strain) were derived from cine CMR images. The extent of LA and RA fibrosis was assessed from 3D late gadolinium enhancement images. AF recurrence was followed-up for 12 months after PVI using either 12 lead ECGs or Holter monitoring. Results: Arrhythmia recurrence was observed in 39 patients (36%) after the 90-day blanking period, occurring at a median of 181 (IQR: 122-286) days. RA remodeling parameters were not significantly different between patients with AF recurrence as compared to patients without AF recurrence after ablation, whereas LA remodeling parameters were (volume, emptying fraction and strain). LA fibrosis had a strong correlation with RA fibrosis (r=0.88, P <0.001). Both, LA and RA fibrosis was not different between patients with and without AF recurrence. Conclusions: RA remodeling parameters were not predictive of AF recurrence after AF ablation. Bi-atrial fibrotic remodeling is present in AF patients and the amount of LA fibrosis had a strong correlation with the amount of RA fibrosis. The presence of bi-atrial fibrotic tissue may be an expression of disease state although no relation with AF recurrence after AF ablation was found.