An inverted left atrial appendage is a rare phenomenon post cardiac surgery. The lesion presents as an additional mass in the left atrium, which would trigger unnecessary concerns and frequently, a battery of tests. The lesion can be easily diagnosed using echocardiography. We report a case of inverted left atrial appendage in a patient post repair of common arterial trunk. Echocardiographic pictures and features which help to identify this lesion as well as to differentiate it from other possible left atrial mass are described. This article aimed to improve the awareness of sonographers toward this rare but possible post operative lesion.