The development of infected coronary aneurismal fistula following stenting seems exceedingly rare. A sirolimus-eluting stent (SES) was implanted in a 70-year-old male patient for acute coronary syndrome. His fever persisted despite treatment with adapted antibiotics. Coronary angiography and 16-multidetector row computed tomography demonstrated the huge right coronary aneurysm forming a fistula to the right ventricle. The aneurysm was excised by surgical treatment. Histopathological examination of the resected mass revealed leucocyte infiltration at the stent site, which lead to the diagnosis of mycotic aneurysm. SESs may play a potential role in locally blunting the innate response to bacterial agents.