Background: Extracorporeal membrane oxygenation (ECMO) is associated with complications that are separate from the underlying diagnoses that require its use. One of the foremost complications of ECMO is a high incidence of bleeding, including alveolar hemorrhage (AH), which is believed to be due to both prophylactic anticoagulation and critical illness-induced systemic coagulopathy. However, akin to systemic inflammatory response syndrome after cardiopulmonary bypass, ECMO causes widespread systemic inflammation and acute lung injury, which likely further predisposes patients to AH. The burden of clinically significant AH among patients on ECMO for advanced lung disease remains unknown. Patients and methods: Charts of patients with advanced lung disease who required ECMO at a single institution were reviewed. The clinical course and variables of patients who developed AH and those who did not were compared. Results: This report describes five patients who developed AH after initiation of venovenous ECMO for refractory hypoxemia. Clinical and laboratory variables did not predict the development or the prognosis of AH. Two of these patients with refractory hypoxemia and AH were treated with pulse-dose corticosteroids, with a dramatic response in one case. Conclusion: The acute decompensation of the patients and response to corticosteroids suggest AH was mediated by a systemic inflammatory process, as opposed to coagulopathy alone. Judicious use of steroids may be considered among select patients who develop AH without symptoms of systemic coagulopathy after initiation of ECMO.