The Hemolytic Uremic Syndrome (HUS) is the prime cause for acute renal failure in children. The HUS is a combination of hemolytic anemia, thombopenia and acute nephropathy: all signs of a thrombotic microangiopathy. Onset occurs generally in infancy and is often associated with severe bloody diarrhea. Most of those cases are caused by Escherichia coli O157:H7 witch produces an exotoxin responsible for the microangiopathy. We discuss the treatment of HUS based on the experience acquired since 1994 in our Paediatric Intensive Care Unit (PICU), University of Liege. The frequent association of dehydration, multi-systemic impairment and reno-vascular hypertension justifies the early admission for PICU-surveillance. This allows the difficult fluid balance management in a setting of renal and pre-renal failure.