OBJECTIVE The objective of this study was to determine the incidence of and specific preoperative and intraoperative risk factors for postoperative delirium (POD) in electively treated vascular surgery patients. METHODS Between March 2010 and November 2013, all vascular surgery patients were included in a prospective database. Various preoperative, intraoperative, and postoperative risk factors were collected during hospitalization. The primary outcome variable was the incidence of POD. Secondary outcome variables were any surgical complication, hospital length of stay, and mortality. RESULTS In total, 566 patients were prospectively evaluated; 463 patients were 60 years or older at the time of surgery and formed our study cohort. The median age was 72 years (interquartile range, 66-77), and 76.9% were male. Twenty-two patients (4.8%) developed POD. Factors that differed significantly by univariate analysis included current smoking (P = .001), increased comorbidity (P = .001), hypertension (P = .003), diabetes mellitus (P = .001), cognitive impairment (P < .001), open aortic surgery or amputation surgery (P < .001), elevated C-reactive protein level (P < .001), and blood loss (P < .001). Multivariate logistic regression analysis revealed preoperative cognitive impairment (odds ratio [OR], 16.4; 95% confidence interval [CI], 4.7-57.0), open aortic surgery or amputation surgery (OR, 14.0; 95% CI, 3.9-49.8), current smoking (OR, 10.5; 95% CI, 2.8-40.2), hypertension (OR, 7.6; 95% CI, 1.9-30.5) and age ≥80 years (OR, 7.3; 95% CI, 1.8-30.1) to be independent predictors of the occurrence of POD. The combination of these parameters allows us to predict delirium with a sensitivity of 86% and a specificity of 92%. The area under the curve of the corresponding receiver operating characteristics was 0.93. Delirium was associated with longer hospital length of stay (P < .001), more frequent and increased intensive care unit stays (P = .008 and P = .003, respectively), more surgical complications (P < .001), more postdischarge institutionalization (P < .001), and higher 1-year mortality rates (P = .0026). CONCLUSIONS In vascular surgery patients, preoperative cognitive impairment and open aortic or amputation surgery were highly significant risk factors for the occurrence of POD. In addition, POD was significantly associated with a higher mortality and more institutionalization. Patients with these risk factors should be considered for high-standard delirium care to improve these outcomes.