Introduction The aim of the study was to analyse prognostic value of laboratory markers of nutritional status in gastrointestinal surgery. Methods We performed a retrospective analysis of clinical and laboratory data of 102 patients admitted to an Intensive Care Unit following elective gastrointestinal surgery. The outcome measures included hospital mortality, infectious complications, surgical complications and length of stay. Results Forty-eight patients had all three laboratory markers of nutritional status determined before surgery and these patients constituted our study group. We found correlations between preoperative serum albumin and hospital mortality, risk of reoperation and urinary tract infection. Preoperative total serum protein correlated with urinary tract infection. Total lymphocyte count was predictive of bacteraemia. No statistically significant correlations were found between markers of nutritional status and length of stay. Conclusions Serum albumin concentration at the lower limit is associated with increased mortality, reoperation, urinary tract infection. Total serum protein predicts urinary tract infection, whereas total lymphocyte count predicts bacteraemia.