We report an 8-year-old girl who presented with hemolytic-uremic syndrome (HUS) as the onset manifestation of acute lymphocytic leukemia (ALL). The patient was admitted to the hospital for renal failure, thrombocytopenia, and anemia during a HUS outbreak. She was discharged 2 weeks later with normal renal function. One month later the girl presented with clinical and laboratory signs consistent with a diagnosis of ALL. The short time interval between HUS and ALL suggests that HUS was probably an early manifestation of acute leukemia.