Background:High-flow nasal cannula (HFNC), which overcomes the disadvantages of the existing low flow mask, is an efficient method that can immediately provide a high volume of heated oxygen to the patient.[1]Therefore, this case reports a case in which HFNC was applied to a pregnant with acute respiratory failure.Case:A 37-year-old woman pregnant (GA 30 + 5 weeks) with twin was diagnosed with preeclampsia. It was decided to perform an emergency Cesarean-section under combined spinal-epidural technique worsening respiratory failure. After delivery, maternal dyspnea was not alleviated applying of O28 L/min via facial mask. Thus, high-flow nasal cannula (HFNC) oxygen therapy was applied (60 L/min, partial pressure of oxygen (FiO2) 80%) and SpO2subsequently rose to 98% and the patient’s dyspnea was resolved.Conclusions:HFNC is a safe device that can effectively provide oxygen to pregnant with acute respiratory failure.