OBJECTIVES Postoperative cognitive decline (POCD) is a well-recognised neurological phenomenon following major surgery. Most commonly seen in elderly patients, it has direct links to increased long-term morbidity and reduced quality of life. Its incidence following open and endovascular abdominal and thoracic aneurysm surgery is unclear. The purpose of this systematic review is to collate available evidence for POCD following abdominal and thoracic aortic surgery, and to identify continuing controversies directing future research. METHODS A MEDLINE search was conducted following the recommendations of the PRISMA guidelines. Terms searched for included but were not limited to: aortic surgery, delirium, postoperative cognitive decline/dysfunction thoracic aortic surgery, abdominal aortic surgery. Reference lists were searched for additional studies. RESULTS Five observational studies were identified from the literature search. Variation in study methods, cognitive test batteries and thresholds set by the study coordinators did not allow for pooled results. In those studies that did find evidence of decline, risk was linked to age over 65 years, presence of postoperative delirium and decreased years in education. CONCLUSIONS Evidence thus far suggests that POCD can affect patients following major aortic, non-cardiothoracic as well as cardiothoracic surgery. Future research should focus on using a validated repeatable battery of cognitive tests and a single defined threshold for POCD to allow pooled analysis and more robust conclusions. Larger, adequately powered studies are required to reevaluate the effect of aortic aneurysm surgery on postoperative cognitive function.