Background: Coronary artery ectasia is the abnormal dilatation of one or more coronary segments. Although the pathogenetic mechanisms underlying CAE are largely unknown, it seems that some of the extracellular matrix degrading enzymes such as matrix metalloproteinases (mmps) can play an important role in the development of this condition. The aim of our study was to evaluate the relationship between MMP-9 and the development of CAE as well as the role played by the inflammatory process in this condition. Materials And Methods: In our retrospective study we have enrolled a series of 79 patients: 47 presented, on coronary angiography, focal or diffuse ectasia of coronary arteries (cases), 32 had a free coronary tree or without hemodynamically significant stenosis (controls). All patients were subjected to blood sampling for the dosage of MMP-9 and Creactive protein (CRP). Results: In our study we found that the most involved coronary artery in CAE was the right coronary artery. Serum levels of MMP-9 were higher in the patients with CAE (5.011 mcg / ml vs. 3.93 mcg / ml, p = 0,07) although not statistically significant, in direct proportion to the number of involved vessels (p = 0.025). Serum CRP levels were higher in patients with CAE (5.12 mg / dl vs. 2.18 mg / dl, p = 0.4) although not statistically significant, in direct proportion to the number of involved vessels (p = 0.001). Conclusions: We found a possible relationship between elevated levels of MMP-9 and CAE, as well as the relationship between levels of MMP-9 and severity of the CAE. Furthermore we found a possible relationship between elevated CRP levels and CAE and there was a directly proportional relationship between the increase of CRP and extension of the CAE.