We report a case of an 85-year-old woman with severe aortic insufficiency caused by structural valve deterioration (SVD) of Medtronic Freestyle stentless aortic bioprosthesis (Freestyle valve) complicated by rheumatic multivalvular heart disease. The patient received an aortic valve replacement by using the modified sub-coronary method with a 21 mm Freestyle stentless porcine valve (Medtronic Inc., Minneapolis, MN, USA), for severe aortic valve stenosis at of the age of 71. The patient developed severe heart failure 14.5 years after the surgery. She was admitted for severe aortic insufficiency caused by a leaflet injury (tear) of the Freestyle valve. She also had had rheumatic mitral stenosis and secondary tricuspid insufficiency with severe pulmonary hypertension. Therefore, treating her heart failure was difficult, but surgery was performed. The leaflets of the stentless bioprosthesis were resected. The insertion of the needle suture into the annulus of the stentless valve was difficult because of calcification of the tissue. An aortic root enlargement procedure was performed using a bovine pericardial patch, enabling the insertion of the needle suture into the Dacron cloth at the bottom of the stentless valve, with 2-0 Ethibond threads and single sutures. We successfully performed an aortic valve re-replacement using an Open Pivot Mechanical Heart Valve (OPHV) 16 mm AP (Medtronic, Minneapolis, MN, USA), which was implanted by using the partial valve-in-valve technique. Simultaneously, mitral valve commissurotomy and tricuspid annuloplasty were performed. The patient had an uneventful postoperative recovery.