Patients with acute kidney injury (AKI) often require initiation of renal replacement therapy (RRT). Currently, there is wide variation worldwide on the indications for and timing of initiation and discontinuation of RRT for AKI. Various parameters for metabolic, solute, and fluid control are generally used to guide the initiation and discontinuation of therapy; however, there are currently no standards in this field. Members of the recently established Acute Kidney Injury Network, representing key societies in critical care and nephrology along with additional experts in adult and pediatric AKI, participated in a 3-d conference in Vancouver in September 2006 to evaluate the available literature on this topic and draft consensus recommendations for research studies in this area. Key questions included the following: what are the indications for RRT, when should acute RRT support be initiated, and when should RRT be stopped? This report summarizes the available evidence and describes in detail the key questions, and some of the methods of answering them that will need to be addressed with the goal of standardizing the care of patients with AKI and improving outcomes.