Background. In the recent ESC/EACTS guidelines, left atrial appendage (LAA) occlusion or exclusion in patients undergoing (thoracoscopic) atrial fibrillation (AF) ablation surgery is recommended. The Watchman device (WD, Boston Scientific, Minnesota) has proved to reduce the risk of thromboembolic events by closing of the LAA, yet no data exist on WD implantation during surgical AF ablation. The objective is to determine if WD implantation is safe and feasible in a hybrid AF ablation setting (i.e., combination of thoracoscopic epicardial surgical and endocardial catheter ablation) and could become subject of further testing to serve as a bail-out in cases in which surgical LAA occlusion methods cannot be applied, due to, for example, severe adhesions. Methods. In this prospective, single center, pilot study, 10 consecutive patients undergoing a hybrid ablation qualifying for LAA exclusion (CHA(2)DS(2)-VASc >= 1) were included. At the end of the hybrid ablation, the LAA was occluded endocardially using the WD. The feasibility endpoint was successful implantation. The safety endpoint concerned major complications. Results. One patient was excluded and replaced because the LAA was insufficiently visible on transesophageal echocardiography. In 10/11 patients, device delivery was successful (mean time: 35 minutes). No major complications occurred. Transesophageal echocardiography after 6 weeks and 6 months showed successful occlusion of the LAA without significant peridevice flow. Conclusion. Implantation of the WD seems to be feasible and safe in the setting of hybrid AF ablation and could be an alternative to epicardial occlusion in surgical AF ablation procedures. Larger studies are required to confirm these findings.