We saw a 34-year-old pregnant woman with acute promyelocytic leukemia, who developed acute respiratory failure from all-trans-retinoic acid (ATRA) syndrome. We applied noninvasive ventilation (NIV, continuous positive airway pressure plus pressure-support ventilation) to try to improve gas exchange, reduce the work of breathing, and prevent intubation. Initially we applied NIV continuously (24 hours a day), then gradually reduced the daily amount of time on NIV as her condition improved. She was discharged from the intensive care unit after 12 days. Three months after hospital discharge she gave vaginal birth to a healthy female baby. NIV was effective and safe for the mother and fetus, and NIV should be considered for respiratory failure in pregnant patients, especially if immunosuppressed.