There is no consensus regarding which risk factors influence the outcome of mitral valve replacement. To study the effects of the referring health care system and other factors on the results of mitral replacement. We included 632 patients operated between 1990 and 2010 receiving the St Jude prosthesis. Patients were divided into three groups, group 1 composed by 180 patients coming from the Public System, group 2 composed by 182 patients coming from the University System and group 3 composed by 270 patients coming from the Private System. Overall operative mortality was 4.3%. There was no difference between groups in mortality. Factors responsible for operative mortality were: emergency operation (Odds Patio (OR): 5.6 P < 0.01) and left ventricular function (according to ejection fraction) grade III to IV (OR: 2.5 p = 0.048). Actuarial survival rates at 1, 5, 10, 15 and 20 years were 95%, 87%, 76%, 61% and 41%, respectively. Risk factors for long-term mortality were diabetes (OR: 3.3 p < 0.01), left ventricular function grades III-IV (OR: 2.6 p < 0.01), New York Heart Association functional class III to PV (OR: 2.1 p < 0.005) and male sex (OR: 1.5 p < 0.032). Referring health care system and type of surgery do not constitute a risk factor for mitral replacement. Risk factors were: emergency surgery, ventricular function grades III-IV, diabetes, functional capacity class III-IV and male sex. Integration of public and private health care systems in a university hospital setting achieves excellent outcomes for complex pathology.