Coronary artery ectasia is the abnormal enlargement of the coronary artery. The prognosis, treatment, and etiology of this disease remain an enigma. There is some evidence to suggest that the incidence of ectasia is increasing, and therefore understanding of this entity needs to improve. This article reviews the current literature on coronary artery ectasia and summarizes the findings. A treatment plan that targets each of the suggested clinical complications is provided. Using multiple indirect observations and current understanding of endothelium-derived relaxation factor, a possible etiology that implicates overstimulation of endogenous nitric oxide is provided. Current literature suggests that ectatic coronary arteries, even without the presence of coronary stenosis, are subject to thrombus formation, vasospasm, and spontaneous dissection. Newer subgroups of ectasia are arising with the use of multiple interventional devices to dilate coronary artery stenosis. By design, these destroy the media of the coronary artery, and it is not clear whether these "iatrogenic" ectatic arteries are subject to the same complications as "idiopathic" coronary artery ectasia. Further investigation is necessary to help define the benefit of the proposed treatment regimen, to clarify the prognosis of these newer groups of "iatrogenic" ectasia, and to confirm or disprove the hypothesis targeting nitric oxide as an etiologic factor.