Abstract Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation of atrial fibrillation (CA-AF) is the most common ablation procedure in Spain. Purpose To analyze the feasibility of performing this procedure on an outpatient approach among patients undergoing scheduled to CA-AF. Methods We compared prospectively the results of all programmed CA-AF procedures in two consecutive periods: from April 1, 2018 to March 31, 2019 (conventional strategy CON-E]: discharge after at least one day of hospitalization, n=100) and from April 1, 2019 to December 31, 2021 (same-day discharge strategy [SDD-E] in which patients were referred for an outpatient procedure by intention to treat, n=320). We established a Primary Efficacy Objective (percentage of patients discharged on the same day in SDD-E), a Primary Safety Objective (cumulative incidence of urgent/unplanned care [UUC] in the 10 days following discharge) and a Secondary Objective (average cost per procedure including day hospital stay, hospitalization and UUC in the 10 days following discharge, using the most recent fees of the Spanish Public Health System). Results Primary Objective of Efficacy: in 358/380 procedures (94%) the patient was discharged within 12 hours after their arrival at the hospital (range of length of hospital stay: 7-10 hours). There was no difference in the early discharge rate between cryoablation vs. radiofrequency (94% vs. 95%; p=0.8). The reasons for patients being hospitalized after ablation in the same-day discharge strategy are displayed in Figure 1. Primary Objective of Safety: Twelve patients (12%) of the CON-E required urgency care within 10 days of discharge, compared to 53(14%) of the SDD-E (p=0.6), most of them due to recurrence of AF. Figure 2. Among SDD-E patients, one was hospitalizated due to severe groin haematoma on day 3 after discharge. The remaining 52 patients with UUC were discharged within 8 hours of arrival at the Medical Center. Secondary Objective: The SDD-E reduced hospital stays: 0 [Interquartilic Range: 0-0] vs. 1 [1-1] (p<0.001), resulting in lower cost per procedure: 552 euros (95% CI: 486-618) vs. 1738 euros (95% CI: 1172-1805) (p<0.001). Conclusions CA-AF can be performed with less than 12 hours of hospital stay in 94% of patients. Compared with the conventional strategy, SDD-E does not increase the rate UUC within 10 days of discharge and is associated with a significant reduction in cost per procedure.