In the last decade, acute kidney insufficiency was renamed to the term acute kidney injury (AKI), which enabled a more accurate and comprehensive description of this condition, emphasizing the acuteness of the event and the entire spectrum of renal dysfunction. Postoperative acute kidney injury is a common complication that occurs in an average of 25% of patients and is associated with a higher frequency of early and late complications, including increased mortality. Risk factors for the development of postoperative AKI are divided into preoperative, intraoperative, and postoperative. These include older age, existing kidney disease and other comorbidities, as well as the type and duration of the procedure. The introduction of the KDIGO diagnostic criteria facilitated early diagnosis, enabled the comparison of epidemiological data and the conducting of further research in this area. According to the KDIGO criteria, the diagnosis is made based on serum creatinine levels and diuresis, and great progress has been made in the development of new, more specific biomarkers of kidney injury. Given that there is still no research-backed evidence on the effectiveness of any specific therapeutic procedure, the best treatment is prevention. An important tool in prevention are periodic targeted assessments of kidney health (Kidney health assessment, KHA). Maintaining the patient's optimal hemodynamic status throughout the entire perioperative period and avoiding nephrotoxins are the basis of renoprotective measures recommended by the KDIGO organization. Their timely implementation reduces the incidence of postoperative ABO. If kidney injury does occur, the therapy is supportive, and in more severe cases, renal replacement therapy is required.