A 7-month-old infant, who underwent repair of coarctation of the aorta four months ago, was readmitted for heart and respiratory failure. Preoperative serial echocardiographic studies revealed progression of mitral valvular and subvalvular stenosis. At operation the mitral valve apparatus was found to be funnel-shaped type of congenital mitral stenosis. Chordae fenestration, papillotomy and commissurotomy were performed. Intraoperative transesophageal echocardiography demonstrated increased inflow through the mitral valve apparatus. Postoperative course was uneventful, and she was discharged 28 days after operation.