Nutritional support in critically ill patients that present with acute renal failure has been a matter of change in recent years. This is due to the increasing and earlier use of extrarenal depuration techniques. Modifications in nutritional and metabolic support regimen aimed at preventing renal failure progression, classically recommended, would not have an indication in these situations but in cases not treated with one of these depurative techniques. Thus, protein intake should be appropriate to the clinical situation, and formulations compounded exclusively by essential amino acids are no longer recommended. Glucose administration should not be different from that recommended in other conditions. Lipids infusion should have a maximum limit of 1 g/kg/day. Thus, the use of standard diets is not problematic in patients treated with depurative techniques. However, the relationship between substrates flow through dialysis membranes and its effect on nutrients demands has not been fully established yet. It is likely that an increase in nutrients intake may be necessary to counteract the obliged loss by depurative techniques. The other way around, the role of these techniques as an appropriate way for nutritional support in critically ill patients remains to be studied.