Few studies have examined the efficacy and safety of cardiac rehabilitation in patients with atrial fibrillation (AF) who underwent AF ablation. We explored the feasibility of additional cardiac rehabilitation after AF ablation in patients with a reduced left ventricular ejection fraction (LVEF). Fifty-four patients with heart failure (HF) and a reduced LVEF (HFrEF) (LVEF < 50%; 67.1 ± 11.6 years; 43 men) who underwent initial AF ablation procedures were included. Fourteen (25.9%) patients underwent cardiac rehabilitation (rehabilitation-group) and the remaining 40 (74.1%) did not (non-rehabilitation-group) after the procedure. The rehabilitation-group patients were relatively older, more likely female ( p  = 0.024), and had more likely a history of an HF hospitalization ( p  < 0.01) and cardiac device implantation ( p  = 0.041). The baseline LVEF was significantly lower ( p  = 0.043) and brain natriuretic peptide (BNP) ( p  < 0.01) and C-reactive protein (CRP) ( p  < 0.01) values were significantly higher in the rehabilitation-group. The 6-min walk distance significantly improved after 21.4 ± 11.5 days of cardiac rehabilitation during hospitalization (226.1 ± 155.9 vs. 398.1 ± 77.5 m, p  = 0.016) without any adverse events. During an 18.9 ± 6.3 month follow-up period, the freedom from AF recurrence ( p  = 0.52) and re-hospitalizations due to HF ( p  = 0.63) were similar between the 2 groups. No death or strokes were observed. During the follow-up period, the LVEF significantly improved similarly in both groups, and the change in the BNP and CRP values significantly decreased in the rehabilitation-group. Despite the rehabilitation-group patients having a more severe HF status, the clinical outcomes and AF freedom were similar between the 2 groups, suggesting the favorable impact of cardiac rehabilitation after AF ablation in HFrEF patients.