Objective: The study is carried out to determine whether the level of IL-6 is altered and in what way after surgery as well as if such a change could be an indicator of increased morbidity after surgical treatment. Materials of the study: Chemiluminesence immuneassay system was used in order to establish IL-6 level in blood samples of 71 patients that underwent abdominal surgery, 36 Laparoscopic Cholecystectomy (LC) and 35 Open Cholecystectomy (OC) at time 0 (before the operation), 1h, 2h, 3h, 6h, 24h and 48h after the operation. Results: Plasma IL-6 levels are significantly increased after OC; we observed 3 cases of post-operative infections, in which IL-6 returned to normal levels 6 days after surgery. Analogous variation to the IL-6 levels was noted for the C-reactive protein levels. Discussion: Laparoscopic cholecystectomy, a so called miniinvasive surgical procedure, is associated to a small increase of IL-6 serum levels and provides better post-operative conditions to the patients by reducing surgical stress and the infectious complications correlated to the surgical procedure. Conclusions: During OC there is a significant higher elevation of IL-6 serum levels than after laparoscopic cholecystectomy. Variation of C-reactive protein serum levels after surgery is analogous to variation of IL-6 levels.