Acute respiratory failure is a life-threatening complication in cancer patients. During neutropenia, patients are at high risk for bacterial pneumonia or invasive fungal infections, when neutropenia is prolonged. A high proportion of patients in whom neutropenia had been complicated by pneumonia will present with substantial respiratory deterioration during neutropenia recovery. Patients with fungal pneumonia and those receiving granulocyte colony-stimulating factor to shorten neutropenia duration may be at higher risk for this acute lung injury/acute respiratory distress syndrome during neutropenia recovery. Routine screening of patient's risk factors is crucial since first symptoms of acute respiratory distress syndrome may occur before biological leukocyte recovery.