Mitral valve aneurysms are very rare complications of bacterial endocarditis. We present the case of an 88-year-old woman with moderate aortic insufficiency and an aneurysm in the anterior leaflet of the mitral valve secondary to endocarditis. After completing a full course of antibiotic, we performed though the aortotomy, mitral leaflet aneurysm resection, repairing the defect with an autologous pericardial patch, and aortic valve replacement by a bioprosthesis. The evolution of the patient was uneventful and was discharged on the ninth postoperative day. (C) 2018 Sociedad Espanola de Cirugia Toracica-Cardiovascular. Published by Elsevier Espana, S.L.U.