Introduction: Left atrial appendage closure (LAAC) device for stroke prevention is a safe and effective alternative to oral anticoagulation (OAC) in patients with atrial fibrillation (AF). The safety of performing LAAC on uninterrupted warfarin (UW) compared to interrupted warfarin (IW) is currently unknown. Hypothesis: Complication rates of performing LAAC on UW vs. IW will be similar. Methods: We reviewed the data from the second half of PROTECT-AF trial, PREVAIL trial, CAP and CAP2 registries. Patients were categorized to the UW group if INR on the day of the procedure was ≥2 and to the IW group if INR was <2. Procedural complications within 7 days of LAAC were reviewed. An association between complications and AC strategy was analyzed. Results: Data from 1580 patients were reviewed and 294 patients (18.6%) received LAAC on UW. The UW group had a mean INR of 2.4±0.4 and IW group had a mean INR of 1.3±0.3. There were several differences in baseline characteristics: lower BMI in the UW group (28.6±5.3 vs 29.5±6.0, p=0.01), fewer patients with hypertension in the UW group (87.1% vs 91.1%, p=0.04), lower HAS-BLED score in the UW group (2.0±1.0 vs 2.1±1.0, p<0.01), and more patients with persistent AF in the UW group (37.1% vs 26.4%, p<0.01). Overall, there were no significant differences in total or individual complication rates between the two groups (UW 5.1% vs IW 6.1%, p=0.59). Although not statistically significant, lower event rates were noted in the UW group for the following: stroke (0% vs 0.3%, p>0.99), pericardial effusion requiring intervention (1.7% vs 1.8%, p>0.99), pseudoaneurysm (0% vs 0.4%, p=0.59), hematoma (0% vs 0.2%, p>0.99), and device embolism (0% vs 0.2%, p=1.0). The UW group had statistically insignificant higher events rates of AV fistula (0.3% vs 0%, p=0.19) and major bleeding requiring transfusion (1% vs 0.5%, p=0.38). In addition, there was no significant difference in periprocedural ischemic stroke (0% vs 0.3%, p>0.99). Conclusion: In this retrospective analysis, no significant difference was observed in procedural complication rates when performing LAAC on UW vs. IW. These results suggest that LAAC can be safely performed without interruption of OAC.