We report a case of atraumatic pneumocephalus associated with prolonged use o f nasal continuous positive airway pressure. Initial symptoms included headache, ataxia, vertigo, and a “ gurgling” sensation in the head; and a CT image sho wed small air bubbles along the falx of cerebrum and adjacent to the temporal ep idural spaces bilaterally. Although no evidence of cerebrospinal fluid (CSF) lea k was either reported by the patient or found at initial clinical examination, s ubsequent nasal discharge tested positive for β 2- transferrin, a finding cons istent with CSF leak in the paranasal sinus region or through the cribriform pla te. To try to prevent infection from an open communication between the paranasal sinuses and intracranial structures, an attempt should be made to localize the anatomic defect. We report a case of atraumatic pneumocephalus associated with prolonged use of nasal continuous positive airway pressure. Initial symptoms included headache, ataxia, vertigo, and a “gurgling” sensation in the head; and a CT image sho wed small air bubbles along the falx of cerebrum and adjacent to the temporal epidural spaces bilaterally. The probable cerebrospinal fluid (CSF) lea k was either reported by the patient or found at initial clinical examination, s ubsequent nasal discharge tested positive for β 2-transferrin, a finding cons istent with CSF leak in the paranasal sinus region or through the cribriform plate. To try to prevent infection from an open communication between the paranasal sinuses and intracranial structures, an attempt should made to localize the anatomic defect.