Implementation of evidence-based peri-operative nutrition in the U.S. is poorly described and hypothesized to be suboptimal. This study broadly describes practices and attitudes regarding nutrition screening/intervention in U.S. gastrointestinal and oncologic surgeons. Nationwide nutritional practice survey of GI/Oncologic surgical faculty. Program response rates were 57% and 81% for colorectal and oncology fellowships, respectively. Only 38% had formal nutritional screening processes in place. Average estimated percent of patients malnourished, receiving nutritional screening, and receiving nutritional supplementation preoperatively were 28%, 43%, and 21%, respectively. University-affiliation (p = 0.0371) and a formal screening process (p = 0.0312) predicted higher preoperative nutritional screening rates. Controversy existed regarding routine use of perioperative immunonutrition, but strong consensus emerged that lack of awareness regarding positive data for immunonutrition impedes usage. U.S. surgeons recognize importance of perioperative nutritional screening and benefits of basic nutrition therapy. However, limited formal nutrition screening programs currently exist indicating a significant need for implementation of nutrition screening and basic nutrition intervention. Further work on education, implementation and identifying clinical research needs for immunonutrition interventions is also vitally needed. This study broadly describes nutritional practices and attitudes of gastrointestinal and oncologic surgeons across the U.S. Surgeons recognize both the importance of proper perioperative surgical nutritional support and the potential value to their practice in terms of outcomes, but this study confirms poor implementation of evidence-based nutrition practices in GI and oncologic surgery programs. This study describes a significant opportunity to capitalize on current favorable surgeon beliefs (and positive published data) regarding the benefit of perioperative nutrition to improve surgical nutrition practice and patient outcomes in the U.S. Copyright © 2016 Elsevier Inc. All rights reserved.