Background: Increasingly, patients with multiple co-morbidities undergo surgery for rectal cancer. We aimed to evaluate if decreased psoas muscle area and volume, as measures for sarcopenia, were associated with postoperative morbidity. Methods: Retrospective review of patients undergoing rectal cancer resection at a tertiary medical center (2007-2015). Variables included demographics, co-morbidities, preoperative psoas muscle area and volume, and postoperative complications. Results: Among 180 patients (58% male, mean age 62.7 years), 44% experienced complications (n = 79), of which 38% (n = 30) were major complications. Malnourished patients had smaller height-adjusted total psoas area than non-malnourished patients (6.4 vs. 9.5 cm(2)/m(2), p = 0.004). Among patients with imaging obtained within 90 days of surgery, major morbidity was associated with smaller total psoas area (6.7 vs. 10.5 cm(2)/m(2), p = 0.04) and total psoas volume (26.7 vs. 42.2 cm(3)/m(2), p = 0.04) compared to those with minor complications. Conclusion: Preoperative cross-sectional imaging may help surgeons anticipate postoperative complications following rectal cancer surgery. (C) 2017 Elsevier Inc. All rights reserved.