The purpose of this paper is to analyze the current perioperative management of diabetes taking into account the guidelines recommendations and the findings of the studies published so far. The prevalence of diabetes is increasing among the population in all age groups. Diseases requiring surgery are common in diabetic patients. The paper correlated the information available to date on the perioperative treatment of diabetes, the postoperative complications and the most frequent errors committed on the management of diabetic patients, aspects with important practical implications. Although hyperglycemia has a significant clinical impact on perioperative morbidity and mortality, glycemic targets and perioperative management have not been well established yet. Further studies are needed to clarify these issues.