Malnutrition results in disorders of programmed cell death influencing the patients susceptibility to infections after major surgery. The preoperative nutrition is a promising way of improving outcome after pancreatic surgery. The purpose of our study was to investigate the influence of enteral nutrition on the changes of apoptotic signaling pathways. The randomized studies were performed in patients operated on for pancreatic cancer receiving standard or enteral immunonutrition. The expressions of Fas/CD95 and TNFRI/CD120a in lymphocytes were assessed by flow cytometry before and on day 1, 3 and 7 after surgery. In comparison to the standard nutrition, the preoperative immunonutrition significantly increased the percentage of CD95 and TNFRI positive lymphocytes after surgery. In conclusion, our findings suggest the up-regulation of proapoptotic signaling systems in lymphocytes of malnourished patients receiving immunonutrition after pancreatic cancer surgery. These changes in apoptotic signaling pathways proteins after immunonutrition may increase lymphocytes dysfunction.