We present a case of a very rare complication of valvular surgery-suture loop jamming. A 77-year-old woman was admitted for surgical treatment of moderate aortic regurgitation, severe mitral regurgitation (MR) and severe tricuspid regur- gitation. She underwent mitral valve replacement (MVR) with porcine bioprosthetic valve and tricuspid annuloplasty by DeVega procedure. Before termination of cardiopulmonary bypass, transesophageal echocardiography (TEE) showed se- vere MR at the center of the bioprosthetic valve along the posterior left atrial wall In addition, echogenic fili- form structure which disturbed the movement of the leaflets was detected. The patient was placed on car- dioplegic arrest again and the heart was reopened, suture loop jamming around the stents of the biopros- thetic valve resulting in significant mitral regurgitation was diagnosed. The implanted bioprosthetic valve was removed and a new bioprosthetic valve was subse- quently re-implanted. Intraoperative TEE provided a visible assessment of mitral prosthetic valve dysfunction and we were immediately able to reach diagnosis of this rare and serious complication-suture loop jamming. Our case makes us recognize suture loop jamming as one of the complications of MVR.