Diffuse large B-cell lymphoma initially appears with intrathoracic manifestations in up to 26% of patients. However, pulmonary involvement with hematologic malignancies rarely manifests clinically as acute respiratory distress syndrome (ARDS). We report a case of diffuse large B-cell lymphoma manifesting as ARDS in a 39-year-old Filipina woman. This case illustrates the importance of including lymphoma in the differential diagnosis of otherwise unexplained ARDS. Early recognition and prompt treatment may affect survival.