Acute kidney injury (AKI) occurs in approximately one-quarter of all patients with severe burn injury (as defined by the RIFLE consensus classification), and approximately 3% of paediatric burn patients. Overall, a three- to six-fold higher mortality for burn patients with AKI is observed, depending on the applied definition. When AKI is defined by the sensitive RIFLE classification, median mortality of AKI is approximately 35%. This chapter describes the general pathophysiology of AKI in burns, particularly the severe form of burn shock, and discusses in addition the roles of intra-abdominal hypertension, rhabdomyolysis, and the potentially negative impact of povidone-iodine burn dressing. Finally the definitions used in burn pathology, the prevention of AKI with a discussion of the fluid therapy in burned patients, and the role of renal replacement therapy in these patients is discussed.