Although they are rare, left coronary artery anomalies can cause complications with high mortality, including arrhythmia and cardiac arrest. Left main coronary artery originates from the non-coronary sinus abnormality is rarely observed. This abnormality has been defined as a benign pathology in the past, although it is described in the literature to cause morbidity and mortality in some cases. We present very rare case of the left main coronary artery arising from non-coronary sinus detected on CCTA.