Background-This study assessed the role of surgical ablation for atrial fibrillation (AF) in decreasing tricuspid regurgitation (TR) and right-sided heart remodeling in patients after mitral valve procedure. Methods and Results-Between 1994 and 2014, 1568 consecutive patients with AF undergoing mitral valve procedure were identified. In 26.0% (n= 408), surgical ablation of AF was used. Propensity-score matching (PSM) was performed on the basis of 41 known perioperative risk variables. Survival, reoperation, stroke, and moderate-to-severe TR, as well as echocardiography indices in long-term follow-up, were compared in 406 matched patient pairs (ablated and nonablated groups). The nonablated group showed significantly higher risks of death (hazard ratio [HR], 1.644; 95% CI, 1.081-2.501; P=0.020), reoperation (HR, 2.644; 95% CI, 1.299-5.466; P=0.008), and moderate-to-severe TR (HR, 1.436; 95% CI, 1.059-1.948; P=0.020), associated with a significantly deteriorated cardiac function, progression of TR, and right-sided heart remodeling after 5-year follow-up. In a subgroup comparison of ablated patients with sinus rhythm versus AF recurrence, a PSM analysis was performed at the 5-year follow-up. The recurrent group showed significantly higher risks of moderate-to-severe TR (HR, 2.427; 95% CI, 1.261-4.671; P=0.008). AF recurrence was associated with progressive TR and significant deterioration in right-sided heart remodeling. Conclusions-In a retrospective PSM analysis, mitral valve disease with AF was associated with TR progression as well as right-sided heart remodeling, which are alleviated by surgical ablation.