Objective During last decades,mechanical ventilation has been an important support in the postoperative management of patients undergoing cardiac surgery.However,a considerable number of patients need mechanical ventilation for a prolonged period after cardiac surgery,and this is associated with increased mortality and morbidity.The study was designed to determine the pre-and perioperative predictors of prolonged mechanical ventilation (PMV) in adult patients undergoing double valve surgery.Methods The retrospective study considered of 2026 adult patients who underwent double valve replacement surgery at Changhai Heart Center from January 1990 to December 2010.PMV is considered as mechanical ventilation period of ＞ 48 hours at postoperative hospital stay here.Results PMV occurred in 11.35 ％ of patients.The total hospital mortality was 4％.The hospital mortality of patients who had undergone double valve replacement surgery required PMV was significantly higher than control (33.5％ vs 0.2％,P ＜ 0.01).And so as comorbidities.Age more than 60 years (OR =1.943),diabetes(OR =1.757),preoperative active endocarditis (OR =3.167),New York Heart Association class higher than 3 (OR =2.464),preoperative critical state(OR =2.556),ejection fraction less than 0.50 (OR =2.026),creatinine greater than 110 μmol/L (OR =2.740),cardiopulmonary bypass time longer than 180 min (OR =3.529) and perioperative intra-aortic balloon pump(OR =18.350) were independent predictors of PMV in our patients.Conclusion PMV is associated with significant comorbidities and increased hospital mortality.Strategies to delineate the patients at risk and to modify these risk factors by prophylactic measures should probably lead to a lower incidence of prolonged mechanical ventilation for adult patients undergoing double valve replacement surgery.