Continuous renal replacement therapy (CRRT) is currently the standard treatment in critically ill patients with acute kidney injury. Extracorporeal techniques in intensive care units sets new tasks for the whole team involved in the treatment and increases the effectiveness of patients treatment. A key role in ensuring the effectiveness of renal replacement therapy plays a nurse. Their role is to conduct the treatment and evaluation of patient response to therapy, including the systematic monitoring of clinical status and selected laboratory parameters or technical aspects of therapy. The aim of the study is presentation the principles of continuous renal replacement therapy in critical care patients. Data were collected based on the current analysis of the Polish and foreign literature, based on PubMed/MEDLINE.