A 59-year-old male was referred for surgery resulting from a paravalvular leak at the mitral position. The patient underwent his first mitral valve replacement with a Bjork-Shiley valve 33 years before this situation arose. He underwent his second mitral valve replacement with a St. Jude Medical mechanical prosthesis for valve thrombosis 10 years later. Serial echocardiography had always shown good results until this time; thus the leak suddenly occurred 23 years after his second mitral valve replacement without any preceding signs. At surgery, a small fistula was observed. The paravalvular leak was successfully repaired by a direct suture repair. Although his postoperative course was complicated by a deep sternal infection, he has fully recovered and currently is in the New York Heart Association class 1 three years after the surgery.