Balloon dilation of native aortic coarctation has been employed safely and effectively in selected patients and with good results during follow-up. However, pseudo-aneurysm formation at the site of dilatation occurs in about 2%-8% of patients. Although the majority of these aneurysms remain stable, they occasionally may increase in size during follow-up, raising concerns in regard to potential rupture, massive bleeding, and death. We report a case of aneurysm formation after balloon dilation of native coarctation of the aorta, treated successfully with the interposition of a tube graft.