Objective: to study the efficacy of third- versus secondary-generation fatty emulsions as part of parenteral nutrition in patients operated on for gastric cancer. Subjects and methods. Envelope randomization was used to make up two groups, each comprising 10 patients, operated on for gastric cancer in the scope of gastrectomy. A control group received parenteral nutrition having the following components: Lipofundin MST/LST 20%, (500 ml daily) + Nutriflex 48/150 (B. Braun) (1000 ml daily, 1744 kcal/day). The study group patients were given Lipoplus 20% (500 ml daily) + Nutriflex 48/150 (1000 ml daily, 1745 kcal/day). Parenteral nutrition was used on postoperative days 1 to 5. Results. Nutritional status evaluation revealed a significant increase in the concentration of total protein and albumin in the control and study group patients on postoperative day 6. The use of both second- and third-generation fatty emulsions caused a significant increase in the concentration of triglycerides on day 6 after surgery; no differences were found between the groups. On day 6 following surgery, there was a significant decrease in IL-4 in both groups (p<0.05). At the same time the Lipofundin MST/LST group showed a significantly lower concentration of IL-4 than did the study group (p<0.05). After termination of a parenteral nutrition course, the study and control groups showed a significant decrease in one of the major pro-inflammatory cytokines — IL-6. Conclusion. In the study group, the serum anti-inflammatory activity of IL-4 was more evident than that in the control group and the proinflammatory activity (IL-6 concentration) decreased, which can support that as compared with the second-generation fatty emulsions, third-generation ones with a balanced omega 3 to omega-6 fatty acid ratio (1:2.7) had a normalizing effect on systemic inflammatory processes and cytokine balance with increased anti-inflammatory and reduced proinflammatory activities. Key words: third-generation fatty emulsions, omega-3/omega-6 fatty acids, pro and anti-inflammatory cytokines.