Diffuse alveolar hemorrhage (DAH) is an uncommon complication of hematopoietic stem cell transplant (HCT) that carries high morbidity and mortality. There are limited contemporary data regarding the incidence, outcomes and risk factors for DAH.What are the incidence, outcomes, and risk factors for developing DAH after HCT?This is a single-center retrospective cohort study of patients who underwent HCT between January 1, 2005 and December 31st, 2016. The incidence and outcomes of DAH development were evaluated. A multivariable logical regression model was used to analyze differences between survivors and non-survivors.Of 4350 patients undergoing first-time HCT, DAH was diagnosed in 99 (2.3%). DAH was seen in 40 of 3536 autologous HCT recipients (1.1 %) and 59 of 814 allogeneic HCT recipients (7.2 %). Mean age was 53 ± 13 years and median time of DAH diagnosis was 126 days (interquartile range: 19-349) post-HCT. In-hospital mortality and mortality one year after DAH diagnosis were 55.6% and 76.8% respectively. DAH diagnosis more than 30 days after transplant (OR: 7.06, 95% CI: 1.65-30.14), low platelet count (OR: 0.98, 95% CI: 0.96-1.0, p = 0.02), elevated INR (OR: 4.08, 95% CI: 0.64-25.88, p = 0.046) and need for invasive mechanical ventilation (OR: 8.18, 95% CI: 1.9-35.21) were associated with higher in-hospital mortality. Steroid treatment did not alter mortality (p= 0.80) or length of stay (p= 0.65). However, among those who received steroids, survival was higher in whose who received modest-dose (<250mg methylprednisolone equivalent/day) compared to those who received high dose (≥250mg methylprednisolone equivalent/day) steroids (OR: 0.21, 95% CI: 0.07-0.72).The mortality of DAH after HCT remains high, and patients can develop DAH long after transplantation. Later development of DAH (>30 days after HCT), need for invasive mechanical ventilation, thrombocytopenia and elevated INR are all associated with worse outcomes.