Acute kidney dysfunction is a common problem in intensive care units. It is not only associated with increased morbidity and mortality but also with increased healthcare costs. Limited healthcare budgets have now raised the issue of how much therapy should be dedicated to these critically ill patients. A precondition for any further discussion on this topic is the question on the long-term outcome and quality of life of these patients. However, only limited data are available in this field. In this review, we will focus on the existing literature, considering not only acute renal failure patients requiring renal replacement therapy but also those patients with mild or moderate impaired renal function. The intention of this review is to show that acute kidney injury is an important but often underestimated disease and a disease that deserves major attention because it is associated with impaired short- and long-term outcome. We will demonstrate that acute kidney injury patients requiring dialysis have a reasonable long-term survival rate and good quality of life. There is no doubt that aggressive intensive care unit treatment is justified in these patients, irrespective of the health costs.