We reviewed the ICU courses of 50 bone marrow transplant recipients treated for respiratory problems. Seven of nine postoperative patients survived compared to one of 40 patients with progressive interstitial pneumonia. Nonsurvivors accounted for 94% of the ICU days, 98% of intubated days, and 99% of blood products used. All survivors were extubated within 4 days. Intensive respiratory care is effective for patients with readily reversible causes of respiratory failure, but is generally futile for patients with progressive interstitial pneumonia. We recommend providing these patients with realistic prognostic estimates early in their treatment.