The aim of this study was to identify risk factors for morbidity and mortality in cardiac valvular surgery. Two hundred and fifty-four patients underwent polyvalvular surgery between May 1996 and December 1998. The mean age was 36.8 years (range 4-66 years) and the group comprised 148 women. Two subgroups were defined: the first (184 patients), characterised by associated mitral and tricuspid valve disease: the second (70 patients), characterised by associated mitral and aortic valve disease with a tricuspid lesion in about half the cases. The risk factors of morbidity and mortality analysed were: Clinical: previous history of cardiac failure, NYHA classification, atrial fibrillation and cardiothoracic index. Doppler echocardiographic: left ventricular end systolic dimension > 50 mm, left ventricular and diastolic dimension > 70 mm, fractional shortening < 28%, ejection fraction < 40%: systolic pulmonary artery pressure > 30 mmHg. Haemodynamic: capillary wedge pressure > 20 mmHg, systolic pulmonary artery pressure > 30 mmHg. The authors identified three statistically significant risk factors for operative morbidity and mortality in polyvalvular cardiac surgery: Previous history of one or more episodes of cardiac failure NYHA functional Classes III or IV fractional shortening < 28%. The morbidity and mortality were lower when patients were operated before these poor prognostic factors were observed.