We describe as case of a 70-year-old man who underwent a percutaneous coronary intervention with stenting, for a severe stenosis complicated by a coronary aneurysm just distal to the stenotic site. Notably, coronary angiogram showed an immediate and progressive reduction in the size of coronary aneurysm. Curved planar reconstruction images of the enhanced CT showed no thrombus and no dissection of the coronary aneurysm. We speculate that coronary stenting might decrease the velocity of coronary flow through the stenosis. Consequently, stenting might attenuate the hydrodynamic wall stress on the aneurysm, and, in addition, improve the degradation of the extracellular matrix structure through the regulation of matrix metalloproteinases. Regression of coronary aneurysm after stenting requires further investigations, because stenting may become a potential means for treating post-stenotic aneurysms.