Central pontine myelinolysis (CPM) is a demyelinating disease of the pons often associated with the demyelination of extrapontine areas of the central nervous system. It typically occurs 0.5-7 days after a rapid increment in serum Na level in hyponatremic patients and may lead to death. A 2.5-year-old child with a diagnosis of acute myeloblastic leukemia developed febril neutropenia, diarrhea, gastrointestinal hemorrhage followed by pulmonary aspergillosis. He could not tolerate enteral nutrition. He was given broad spectrum antibiotics and antifungal treatment. Laboratory tests showed electrolyte abnormalities including hyponatremia, hypokalemia and hypophosphatemia in a chronic course. Twenty three days after a rapid correction of hyponatremia (16 mEq/L/24 h) he revealed flask quadriparesis, disphagia, mutism, irregular respiratory pattern and loss of cough and gag reflex. Cranial magnetic resonance showed central pontine and extrapontine myelinolysis. He required mechanical ventilation and then he regained his neurologic functions. He completed chemotherapy protocol and underwent hematopoietic stem cell transplantation. After 2.5 years of the occurrence of CPM he is in completely normal physical and neurological status. CPM is a very severe but rare disorder in children with underlying disease. In the presence of multiple etiologic factors it may reveal a delayed onset and optimum outcome can be seen even in the severe clinical presentation with adequate intensive support.