The intensive care unit (ICU) is a common source of high-acuity nephrology consultations. Although advanced chronic kidney disease is associated with increased ICU mortality, the prognosis of acute kidney injury (AKI) requiring renal replacement therapy is far worse, with short-term mortality rates that often exceed 50%. As such, it is essential that practicing nephrologists be comfortable caring for critically ill patients. This Core Curriculum article emphasizes the developments of the last decade since the last Core Curriculum installment on this topic in 2009. We focus on some of the most common causes of AKI in the critical care setting and use these AKI causes to delve into specific topics most relevant to critical care nephrology, including acute respiratory distress syndrome, extracorporeal membrane oxygenation, evolving concepts in fluid management, and shock. We conclude by reviewing the basics of palliative care nephrology and dialysis decision making in the ICU.