The kidney is a common "victim organ" of various insults in critically ill patients. Sepsis and septic shock are the dominant causes of acute kidney injury, accounting for nearly 50 % of episodes of acute renal failure. Despite our substantial progress in the understanding of mechanisms involved in septic acute kidney injury there is still a huge pool of questions preclusive of the development of effective therapeutic strategies. This review briefly summarizes our current knowledge of pathophysiological mechanisms of septic acute kidney injury focusing on hemodynamic alterations, peritubular dysfunction, role of inflammatory mediators and nitric oxide, mitochondrial dysfunction and structural changes. Role of proteomics, new promising laboratory method, is mentioned.