Respiratory failure (RF) requiring mechanical ventilation (MV) is a frequent, critical complication of bone marrow transplantation. RF has a global survival rate at 6 months of between 2 and 5%, depending on the patient group. Recently, a type of RF associated with hemoperipheric recovery has been described. This is known as engraftment syndrome. We have documented two cases of RF that follow the engraftment syndrome criteria and needed MV. Both patients had all the features identified for a bad prognosis described in the literature. Both are alive after being discharged from the hospital 20 months ago.