Idiopathic pulmonary fibrosis (IPF), a chronic interstitial lung disease of unknown etiology, generally leads to a progressive decline in respiratory function and early mortality. Some patients may experience acute exacerbation (AE-IPF) during the disease, leading to severe acute respiratory failure (ARF).  Some recently developed strategies to improve oxygenation and to reverse CO2 retention have improved the management of ARF in adult patients. High-flow nasal cannula (HFNC) oxygen therapy, which delivers heated, humidified inspired gas at a high flow rate at a precise fraction of inspired oxygen (FiO2), is being increasingly utilized to correct severe, refractory hypoxemia in patients with respiratory distress due to a variety of causes. HFNC reduces the anatomic dead space and increases positive end-expiratory pressure (PEEP), allowing higher concentrations and oxygen flow. Spontaneous pneumothorax (PNX) has been observed in patients with acute IPF exacerbation receiving HFNC. Although fibrosis itself may contribute to PNX, high PEEP generated by HFNC is a risk factor for increased alveoli damage and air-leak. We present three cases of spontaneous PNX in patients with AE-IPF treated with HFNC.