The anatomic details and pathophysiological patterns of most coronary artery anomalies (CAAs) are presently well known. On the contrary, few data exist on the clinical relevance of different CAAs which necessitate a proper management and follow-up protocol. Clinical, invasive and interventional cardiologists often continue to encounter CAAs as incidental findings during routine diagnostic work up for other cardiac diseases and are sometimes unable to fit them into a specific pathophysiological context and a corresponding management protocol. In describing CAAs the authors have focused their attention on the clinical relevance in order to suggest a practical clinical classification based on four classes of clinical significance: I-benign, II-relevant (related to myocardial ischemia), III-severe (related to sudden death), IV-critical (association of classes II and III with superimposed coronary artery disease).