The objective of the study was to investigate the alterations in systemic production of IL-6, sTNFRI and IL-1ra before and following pancreaticoduodenectomy in patients receiving enteral nutrition with and without postoperative complications. The prospective studies included 29 patients with pancreatic cancer who had undergone pancreaticoduodenectomy. In the routine evaluation of nutritional status a weight loss, BMI, albumin concentration and lymphocyte count were taken into account. Serum concentrations of IL-1ra, sTNFRI (p55) and IL-6 were measured by ELISA. In enteral nutrition Nutridrink, Nutrison and Stresson (Nutricia) were applied. Thirteen of the 29 patients developed postoperative complications (included 2 subjects receiving enteral nutrition). Sixteen uninfected patients (including 10 patients with enteral nutrition) recovered from surgery without postoperative complications. This study provided the following information: a) higher preoperative serum IL-6 and IL-1ra concentrations in patients without postoperative complications receiving enteral nutrition, b) lack of significant increase in IL-6 and IL-1ra levels after major surgery in patients with uneventful postoperative course receiving pre- and postoperative enteral nutrition, and c) high early postoperative increase of serum IL-6 (520.72±511 pg/mL, p=0.01), IL-1ra (4860±2005 pg/mL, p=0.01) and sTNFRI (4105.35± 1544 pg/mL, p=0.01) levels over the preoperative values in patients without preoperative and early postoperative enteral nutrition who developed serious complications after surgery. We suggest that pre- and postoperative enteral nutrition protects against the development of postoperative complications and SIRS- type reaction after Whipple procedure. Measurement of serum IL-6, IL-1ra and sTNFRI concentrations on the 1^st day after pancreaticoduodenectomy may predict the development of postoperative infectious complications often requiring re-operations.