Introduction: Diabetes or diabetes mellitus is the most widespread chronic metabolic disease. It is the main cause of death and reduced life expectancy. With the growing prevalence of diabetes, throughout their lives, approximately 25% of diabetes patients require surgical treatment. Surgical treatment is one of the ways of treatment that interfere with a patient’s entire organism. From their perspective, this is a sudden change that they have to adapt to, requiring a certain amount of time, strength and support. It is important that an individual treatment plan is prepared for each diabetes patient prior to the surgery. Well-organised perioperative medical care and a multidisciplinary approach ensure safe surgery, without acute and chronic complications. Aim: The aim of this paper is to present diabetes patient treatment before a planned surgery under general anaesthesia. Methods: This paper uses the descriptive work method. A thematic review of scientific and professional literature in Slovene and English was conducted, searching through COBISS, PubMed, CINAHL and Science Direct online databases and in the Google Scholar online search engine, using the selected keywords. Results: Surgery is an important diabetes treating option. The level of blood glucose should be monitored all the time in diabetes patients that are to undergo surgical treatment, in order to achieve normoglycaemia. All perioperative care activities and quality organisation of a multidisciplinary team ensure efficient surgical treatment, prevent acute and chronic complications and lead to rapid recovery. Discussion and conclusion: A key tool combining disciplines and harmonising approaches is guidelines for clinical treatment of diabetes, which Slovenian professionals regularly update in accordance with scientific progress and newly developed approaches. Findings of this research prove the importance of perioperative medical care for quality diabetes patient treatment and its course. Quality perioperative treatment can be achieved with the cooperation of a multidisciplinary team with the patient and their relatives. A multidisciplinary type of treatment improves patient care, achieves better clinical results, ensures a more accurate disease diagnosis, improves mental and physical state of the patient and reduces mortality rate.