Previous studies have reported mortality rates of about 80% in hematopoietic stem cell transplant recipients with diffuse alveolar hemorrhage. This retrospective study describes the clinical course of 48 such patients: mean age 47.7 years, 52% autologous transplant and 67% peripheral stem cell source. The hemorrhage occurred within one month of transplant in 28 patients. Symptoms included dyspnea in 92%, fever in 67%, cough in 56%, and hemoptysis in 15%. Intensive care unit admission was required in 85% and mechanical ventilation in 77%. Most of the patients were treated with intravenous methylprednisolone 1 g daily for 3 days and then tapered off after a median of 22 days. The hospital mortality was 48%. The cause of death was respiratory failure in 15 of the 23 deaths. Mortality was 28% in autologous compared with 70% in allogeneic transplant recipients (p = 0.0040). The mortality rate of patients whose hemorrhage occurred within the first 30 days of transplant was 32% compared with 70% of those with late hemorrhage (p = 0.0096). This study shows that survival rate of hematopoietic stem cell transplant recipients with diffuse alveolar hemorrhage is better than previously reported, and that early onset and autologous transplant are favorable prognostic indicators.