The respective roles of cardiologist and cardiac surgeon in the operative management of any specific case of mitral valve disease are variable. The range from the prevalent complete predominance of the surgeon through meaningful interaction between the two, concerning the timing and type of surgery, to predominance of the cardiologist when the surgeon accepts a role of technician. There are a number of scenarios in mitral valve surgery in which a reduced risk of postoperative hospital mortality and morbidity, by performing the simplest and shortest procedure, have to be balanced against enhanced peri-operative problems when other aspects are addressed that improve, sometimes markedly, the long-term prognosis. It is argued that a mildly stenotic aortic valve should often be replaced at the time of mitral valve surgery; that despite technical difficulties and a variable long-term postoperative course, surgeons should continue to repair rather than replace the mitral valves of young patients with severe mitral regurgitation despite the invariable presence of active rheumatic carditis; and that excess leaflet tissue and lax chordae in cases of degenerative mitral regurgitation are casually related to multifocal and potentially fatal ventricular ectopy. The crucial but neglected role of an organically abnormal tricuspid anulus in allowing dilatation and hence tricuspid regurgitation in patients with rheumatic mitral valve disease is considered in some detail. Such dilatation may occur late after mitral valve surgery for rheumatic disease, has generally and incorrectly been regarded as "functional" tricuspid regurgitation, contributes importantly to the postoperative "restriction-dilatation syndrome" and can be effectively prevented, or when once established then surgically managed, by a modified De Vega anuloplasty. Finally it is believed that, unlike mitral balloon valvuloplasty in selected instances, successful tricuspid balloon valvuloplasty can never be accomplished without causing significant tricuspid regurgitation and the procedure should be abandoned.