Rhabdomyolysis with myoglobinuria is an uncommon complication of bacterial sepsis. The authors describe three pediatric acute lymphoblastic leukemia patients who developed rhabdomyolysis during a neutropenic sepsis episode due to Escherichia coli. All of the patients needed hemodynamic supportive treatment because of septic shock. Broad-spectrum antibiotics, alkalinization, and intravenous fluid therapy was given. One patient with renal insufficiency died, despite aggressive treatment. Muscle pain and dark urine color should alert physicians to the possibility of rhabdomyolysis in immunocompromised patients with sepsis. Early and appropriate treatment is critical in these patients to prevent renal failure and shock, and for a better outcome.