OBJECTIVES:  To evaluate the economic burden of hospital complications for six chirurgical procedures, using administrative hospital information system (HIS) of Italy. Estimate the increase of length of hospital stay caused by postoperative infections. METHODS: From HIS, which collects all information about hospital admission in public and private hospitals of Italy, we selected all hospital discharges with DRG of “appendectomy”, “cholecystectomy”, “small and large bowel procedures”, ”stomach, esophageal and duodenal procedures” and “caesarean section”, with or without complications. For the selected hospitalizations, we identified the presence of Postoperative Infection (ICD9CM code 998.59) in main or secondary diagnosis. The cost of each event was estimated through National tariff of hospital performances. RESULTS: We selected about 888,000 hospital discharges for the selected DRG in three years, the proportion of complicated DRG was 17.2%. The mean increment of costs due to complications was estimated in about € 3,400 euros. The greater difference was registered for stomach, esophageal and duodenal procedures (about € 5,800) while the smallest differences was estimated for Caesarean section (€ 690). Furthermore, the presence of another postoperative infection cause a mean increment of length of hospital stay of about 8 days, this is true both in complicated and no complicated DRG. CONCLUSIONS:  The hospital complications for the six surgical procedures analysed in the study, involve significant increments of hospitalization costs, furthermore the presence of postoperative infection cause an increment of 8 days of length hospital stay.