Objective: To evaluate the association between patient characteristics and both clinical and economic outcomes in patients having abdominal aortic surgery in Maryland between 1994 and 1996. Design: Retrospective study using an administrative data set. Setting: All Maryland hospitals that performed abdominal aortic surgery from 1994 through 1996 (n = 46). Participants: All patients who had abdominal aortic surgery in Maryland from 1994 through 1996 (n = 2,987). Interventions: None. Measurements and Main Results: The authors obtained discharge abstracts from the Maryland Health Services Cost Review Commission for patients with a primary procedure code for abdominal aortic surgery. Primary outcome variables were in-hospital mortality, hospital length of stay, and intensive care unit (ICU) days. The authors evaluated the following groups of independent variables: demographic characteristics, severity of illness, comorbid disease, and preoperative admission days. In multivariate analysis, independent predictors of in-hospital mortality were age 61 to 70 years (odds ratio [or], 3.1; confidence interval [ci], 1.4 to 6.9), age 71 to 84 years (OR, 7.2; CI, 3.7 to 14.1), age 85 years or older (OR, 9.3; CI, 3.9 to 21.9), ruptured aneurysm (OR, 5.3; CI, 3.5 to 8.2), urgent operation (OR, 2.3; CI, 1.1 to 5.2), emergent operation (OR, 3.0; Cl, 1.9 to 4.7), mild liver disease (OR, 4.6; CI, 2.0 to 10.9), and chronic renal disease (OR, 6.9; CI, 3.9 to 12.1). Hospital admission 1 to 2 days preoperatively was not associated with a difference in in-hospital mortality but was associated with a 31% increase in hospital days (CI, 23% to 40%) and a 38% increase in ICU days (Cl, 19% to 60%). Conclusion: In patients having aortic surgery, several patient characteristics such as mild liver disease and chronic renal failure, were associated with increased in-hospital mortality and length of stay. The practice of admitting patients to the hospital 1 to 2 days before surgery should be reevaluated because this was not associated with reduced in-hospital mortality but was associated with increased hospital and ICU stay.