Background: Immunonutrition not only a nutritional supply for patients but it is a therapy which should be started as early as possible especially in expected malnutrition following gastrointestinal cancer surgery. Objectives: Evaluation the effect of imunonutrition in gastrointestinal tract cancer surgery patients on postoperative complications. Patient and Methods: A prospective randomized trial was carried out on 45 patients who were chosen and classified randomly into three groups each of them included 15 patients as the followings: Group I received total parenteral nutrition immediately postoperative for 7 days in the form of carbohydrate, proteins, fat (Intralipid 20%), electrolytes, trace elements and glutamine intravenous in central venous catheter. Group II received nutrition like group one except that lipid was administered in a new formula containing soya bean oil, medium chain triglyceride, olive oil and fish oil. Group III received nutrition in the same formula of group II but it was started 7 days preoperative and continued for 7 days postoperative. Assessment parameters such as body weight and complications were recorded. Results: No significant difference between three groups concerning age and sex. A significant effect of time on body weight collectively was proved. There is significant group interaction between 3 groups. Body weight showed a significant drop both in group I and group III, but not in group II. Concerning postoperative complications there were no statistical significance between three groups. There was a decrease in the rate of pulmonary tract infection in group III compared to other groups but the decrease was not statistically significant. Only one case of urinary tract infection was reported in group II and one case of intra-abdominal infection in group I. Conclusion: There was positive impact of enteral immunonutrition on reduction of postoperative complications compare to basic caloric requirements (Intralipid postoperative). These findings suggest its use as a method of choice during the postoperative period.