Background. Atrial appendage (LAA) occlusion is a therapeutic option for thromboembolic prevention in atrial fibrillation (AF) patients who have contraindications to oral anticoagulation (OAC) or high risk of bleeding. Traditionally, thrombus in the LAA has been considered a contraindication for LAA occlusion. Recently, resistant thrombus formation in patients using OACs was suggested as an indication for LAA occlusion. Methods and Results. In this single-center study, we evaluated the safety and efficacy of LAA occlusion in patients with a thrombus in the LAA. Twelve non-valvular AF patients who had a thrombus in the LAA were enrolled. The mean age was 71.8 years (range, 62-83 years). Permanent AF was present in all patients. Mean CHA(2)DS(2)-VASc score was 4.9 (range, 2-8) and mean HAS-BLED score was 4.8 (range, 3-6). Thrombi in the LAA were classified as type 1 (proximal to mid) and type 2 (distal) in 3 and 9 patients, respectively. Median follow-up duration was 12 months (interquartile range, 6-24 months). LAA occlusion was performed successfully with Amplatzer Amulet device without any significant periprocedural adverse events in all 12 patients. Transesophageal echocardiography (TEE) was performed at 1 and 6 months post procedure. Cardiovascular and all-cause mortality, significant ischemic cerebrovascular events, worsening heart failure, and major bleeding events did not occur during follow-up. Device-related thrombus was not observed with TEE in any patient. Conclusion. Our study showed that percutaneous LAA closure could be a therapeutic option for patients with resistant LAA thrombus.