This study aimed to assess the association between frailty and clinical outcomes in patients with atrial fibrillation (AF) who undergo catheter ablation. We conducted a retrospective cohort study using the National Inpatient Sample database from 2017 to 2019. Adult patients hospitalized with a primary diagnosis of AF who underwent catheter ablation were included. Frailty was assessed using the Hospital Frailty Risk Score. The primary outcome was the presence of any complication (vascular, cardiac, respiratory, neurologic, or infectious), and secondary outcomes were in-hospital mortality, length of hospital stay, and hospital charges. A total of 21,075 weighted hospitalizations were included, and 14% were classified as intermediate or great risk of frailty. Patients with intermediate (adjusted relative risk 2.86, 95% confidence interval 2.24 to 3.67) and great (adjusted relative risk 6.68, 95% confidence interval 3.77 to 11.84) risk of frailty were associated with a greater risk of any complication than that of the group at less risk. The in-hospital mortality rate was significantly higher among patients at intermediate risk than among those at less risk of frailty (2.6% vs 0.1%, p <0.001). Patients with great and intermediate risk had significantly longer hospital stays than did the group with less risk (median 14 vs 5 vs 2 days, p <0.001), in addition to greater total charges (median $189,072 vs $161,598 vs $130,672, p <0.001), respectively. In conclusion, frailty was associated with a greater risk of poor short-term outcomes in patients with AF who underwent catheter ablation. The Hospital Frailty Risk Score is a useful tool for identifying patients at increased risk of adverse events and could aid in preoperative optimization and postoperative management.