INTRODUCTION The aim of this study was to determine if cardiopulmonary exercise testing (CPET) predicts 30-day and midterm outcomes when assessing suitability for abdominal aortic aneurysm (AAA) repair. METHODS Since July 2006 consecutive patients from a single centre identified with a large (≥5.5cm) AAA were sent for CPET. Follow-up was completed on 1 August 2009. Univariate logistical regression was used to compare CPET parameters with the Detsky score, the Acute Physiology and Chronic Health Evaluation (APACHE) II score and the Vascular Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (VPOSSUM) in predicting predefined early and late outcome measures. RESULTS Full data were available for 102 patients (93% male, median age: 75 years, interquartile range (IQR): 70–80 years, median follow up: 28 months, IQR: 18–33 months). Ventilatory equivalents for oxygen and APACHE II predicted postoperative inotrope requirement (p=0.018 and p=0.019 respectively). The Detsky score predicted the length of stay in the intensive care unit (p=0.008). Midterm (30-month) survival was predicted by the anaerobic threshold (p=0.02). CONCLUSIONS CPET provided the only means in this study of predicting both 30-day outcome and 30-month mortality. CPET could therefore become an increasingly important tool in determining the optimum management for AAA patients.