This study analyzes data from New York State's new Cardiac Surgery Reporting System, which contains information about cardiac preoperative risk factors, postoperative complications, and hospital discharge. The purposes of the study were to determine the set of significant clinical risk factors and to identify cardiac surgical centers most likely to have serious quality-of-care problems. Significant risk factors for in-hospital death were age, gender, ejection fraction, previous myocardial infarction, number of open heart operations in previous admissions, diabetes requiring medication, dialysis dependence, disasters (acute structural defect, renal failure, cardiogenic shock, gunshot), unstable angina, intractable congestive heart failure, left main trunk narrowed more than 90%, and type of operation performed. Four of the 28 hospitals had significantly higher mortality rates than expected, given the risk factors of their patients. Subsequent site visits and medical record reviews confirmed that these facilities had high percentages of quality-of-care problems among cases resulting in mortality.