Abstract Background Atrial fibrillation (AF) catheter ablation among cancer patients was evaluated only in a few small studies. We investigated the extent and in-hospital outcomes of AF catheter ablation procedures among cancer patients. Methods Using the National Inpatient Sample (NIS) database, patients who underwent AF catheter ablations in the US between 2016 and 2019 were identified using ICD-10 codes. Sociodemographic, clinical data, in-hospital procedures and outcomes as well as in-hospital mortality and length-of-stay (LOS) were collected. Baseline characteristics and in-hospital outcomes comparison between patients with and without cancer was performed. Results An estimated total of 36630 patients underwent AF catheter ablation between 2016-2019 in the US. Of them, 585 (1.6%) had cancer diagnosis. Compared with non-cancer patients, patients with cancer were older, had higherCharlson Comorbidity Index, as well as CHA2DS2-VASc and ATRIA bleeding indices scores (Table 1). Higher rate of total complications was observed in cancer patients (10.3% vs 7.0 , p=0.002) driven mainly by more bleeding and infectious complications. LOS was also significantly longer in cancer patients (5.5 + 6.3 vs. 3.1 + 3.4 days, p<0.001). However, no significant differences in cardiac or neurological complications as well as in-hospital mortality rates were observed and were relatively low in both groups (Table 2). Conclusion AF catheter ablation in cancer patients is associated with higher bleeding and infectious complication rates, but not with increased cardiac complications or in-hospital mortality rates in a nationwide, all-comer registry.