Objectives: Resistin, a hormone secreted from adipocytes and considered to be a likely cause of insulin resistance, has recently been accepted as a proinflammatory cytokine. This study aimed to determine the correlation between resistin levels in patients with intra-abdominal sepsis and mortality. Methods: Of 45 patients with intraabdominal sepsis, a total of 35 adult patients were included in the study. This study was undertaken from December 2011 to December 2012 and included patients who had no history of diabetes mellitus and who were admitted to the general surgery intensive care units of Gazi University and Bülent Ecevit University School of Medicine, Turkey. Evaluations were performed on 12 patients with sepsis, 10 patients with severe sepsis, 13 patients with septic shock and 15 healthy controls. The patients’ plasma resistin, interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), procalcitonin, lactate and glucose levels and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were studied daily for the first five days after admission. A correlation analysis of serum resistin levels with cytokine levels and APACHE II scores was performed. Results: Serum resistin levels in patients with sepsis were significantly higher than in the healthy controls (P <0.001). A significant correlation was found between serum resistin levels and APACHE II scores, serum IL-6, IL-1β, TNF-α, procalcitonin, lactate and glucose levels. Furthermore, a significant correlation was found between serum resistin levels and all-cause mortality (P = 0.02). Conclusion: The levels of resistin were significantly positively correlated with the severity of disease and were a possible mediator of a prolonged inflammatory state in patients with intra-abdominal sepsis.