A 86-year-old woman with first diagnosed atrial fibrillation (AF) underwent mitral valve annuloplasty 10 years before was admitted to our Unit due to congestive heart failure. Trans-thoracic echocardiogram (TTE) revealed a large fluctuant echogenic mass in the posterior wall of the left atrium. Trans-oesophageal echo (TOE) showed the origin of the mass within the left atrial appendage. An adjusted dose of the novel oral anticoagulant (NOAC) apixaban, was prescribed. A complete disappearance was appreciated by examination at 12 weeks after the first drug administration. Although apixaban, resulted superior to warfarin in preventing stroke and thrombo-embolic events in patients with non valvular AF, while causing less bleeding, few data are actually available regarding the efficacy and safety of this drug in left atrium and appendage thrombosis management. Our report shows that this NOAC could be a simple and useful option to manage huge atrial trombosis in very elderly patients.