background: Multiple complications occur after repair of a thoracoabdominal aortic aneurysm, the most common of which is respiratory failure. methods: One hundred consecutive thoracoabdominal aneurysm repairs were studied retrospectively using univariate, bivariate, and multiple logarithmic regression analyses to identify factors associated with respiratory failure. results: The mean of days of intubation was 5.8 ± 0.8 (mean ± SEM), with a median of 2 days. Patients who developed respiratory failure (21%) had a 42% mortality compared with a 6% mortality in patients who did not develop respiratory failure (P <0.001). Statistical analysis demonstrated a significant (P <0.01) age difference between those with respiratory failure (71.9 ± 1.6 years) and those without (65.5 ± 1.3 years). Type II aneurysms occurred in 32% of patients, a 3.2-fold increase in relative risk compared with all other types of aneurysm. Seventy-nine percent of patients had a significant smoking history. Low forced vital capacity and forced expiratory volume were both significant variables in predicting respiratory failure, but neither chronic obstructive pulmonary disease nor emphysema was a predictive variable. Intraoperative blood transfusion (mean 10.5 ± 0.8 units) was associated with respiratory failure (P = 0.05). Postoperative complications associated with respiratory failure were creatinine elevation and pneumonia. conclusion: We conclude that the independent variables affecting respiratory failure after thoracoabdominal aneurysm repair are age, type of aneurysm, excessive intraoperative blood transfusions, creatinine elevation, and postoperative pneumonia.