Tumor lysis syndrome is a serious and dangerous complication usually associated with antiblastic treatment in some malignancies characterized by high cell turn-over. Mild or severe electrolyte abnormalities including high serum levels of uric acid, potassium, phosphorus, creatinine, bun and reduction of calcium can be responsible for multi-organ failure, involving mostly kidneys, heart and central nervous system. Renal damage can be followed by acute renal failure, weight gain, progressive liver impairment, overproduction of cytokines, and subsequent maintenance of multi-organ damage. Life-threatening acute respiratory failure associated with tumor lysis syndrome is rare. We describe a child with T-cell acute lymphoblastic leukemia, who developed an unusually dramatic tumor lysis syndrome, after administration of the first low doses of steroid, that was rapidly associated with severe acute respiratory distress syndrome. Subsequent clinical course and treatment modalities that resulted in the gradual and full recovery of the child are also described.