We present the case of a patient with infective endocarditis anesthetized for replacement of severely regurgitant aortic valve. Intraoperative transesophageal echocardiography revealed a new diagnosis of severe secondary mitral regurgitation. After aortic valve replacement and tricuspid valve repair, severe mitral regurgitation resolved rapidly without any intervention. In multivalvular disease, instant spontaneous resolution of secondary mitral regurgitation is possible after surgical correction of an aortic regurgitation causing left ventricular volume overload.