Coronary artery ectasia (CAE) is defined as localized coronary dilatation that exceeds the diameter of normal adjacent segments or the diameter of the patient's largest coronary vessel by 1.5 times. The incidence of CAE varies from 1.5 to 5% in most literature; however, it was reported as high as 10% in some nations. Although, the pathogenesis of CAE is not fully understood, atherosclerosis remains the main association with CAE, in the western world. Kawasaki disease is another common cause of acquired heart disease in children, causing CAE. Kawasaki disease prevalence is overstated by its geographical distribution. Current modalities of investigation looked at the anatomical distribution of the disease and its possible ischemic effects. Biomarkers were studied in depth to explain the active nature of CAE; however, the common association with atherosclerosis weakens its significance. Here we reviewed CAE, its prevalence, relationship to other systemic anomalies in the vascular bed, pathogenesis and diagnostic tools currently in use.