Renal replacement therapies (RRTs) are frequently employed for treatment of patients suffering from acute kidney injury in the intensive care unit (ICU). Multiple modalities of RRT are currently available. These include intermittent hemodialysis, continuous renal replacement therapies, and hybrid therapies, such as sustained low-efficiency dialysis. Because of the high complexity of ICU patients, physicians must be aware of the limitations and complications of both intermittent and continuous dialysis modalities that can contribute to patient morbidity and mortality. In this article, we highlight the recognized complications of RRTs and the treatment approach to these complications. © 2011 Wiley Periodicals, Inc..