AbstractA 74‐year‐old woman, with a history of aortic valve replacement and open mitral commissurotomy due to rheumatic aortic and mitral stenosis, presented with dyspnea. She developed severe tricuspid regurgitation (TR), requiring tricuspid valve replacement (TVR). Despite an uneventful postoperative course, she was readmitted for dyspnea 2 months later. Trans‐thoracic echocardiogram revealed severe mitral regurgitation (MR), despite mild MR at the time of TVR, which has not been previously reported. The main MR mechanism was increased left ventricular preload due to improved TR. Increased diuresis has controlled her congestive heart failure, but her MR remained moderate.