© 2016 Elsevier Inc. All rights reserved. Background Postoperative ileus (POI) has a significant impact on patient wellbeing, and with a 15% incidence in colectomy patients costs US hospitals >$1.3 billion per year. Although some causative mechanisms have been identified, little is known about what places patients at risk for ileus. We aimed to identify factors that independently influence the development of POI. Materials and methods Patients who underwent elective surgery between 2011 and 2012 were identified from the colectomy-specific American College of Surgeons National Surgical Quality Improvement Program database. Descriptive statistics were calculated, and demographics, comorbidities, preoperative treatments, and operative characteristics were evaluated as risk factors using multivariate analyses. Results A total of 9734 patients were included in this analysis; 1364 (14%) were found to have POI. Patients who developed an ileus were more likely to develop any postoperative complication, to be readmitted, and require reoperation compared with patients without POI. In addition, we identified 13 independent risk factors for POI. Conclusions Five modifiable risk factors for development of POI were identified as follows: smoking, weight loss, preoperative oral antibiotics, mechanical bowel preparation, and surgical approach. These identifications provide insight into possible targets for preoperative modification, which may lead to improvements in patients' quality of life and influence outcomes such as postoperative complications, readmission, and reoperation.