Patients with cancer suffer alterations of their metabolic state and nutritional depletion. This review was designed to evaluate the effect of different nutritional regimens on surgical outcomes.Review of the literature on parenteral and enteral nutrition and immunonutrition in patients with gastrointestinal cancer undergoing major surgery. The outcome measures were postoperative complication rate and length of hospital stay.Postoperative enteral nutrition reduced significantly the rate of postoperative complications compared with parenteral feeding only in malnourished subjects. Several metaanalyses and randomized trials showed that preoperative and perioperative use of an enteral formula containing arginine and omega-3 fatty acids has a significant beneficial effect on surgical outcome in both well-nourished and malnourished patients.Enteral immunonutrition should represent the first choice to nourish surgical subjects.