Continuous positive airway pressure (CPAP) therapy is very often the treatment of choice for obstructive sleep apnoea (OSA). The association between intracranial hypertension and spontaneous cerebrospinal fluid (CSF) rhinorrhoea is being increasingly recognized among patients with OSA. However, spontaneous CSF rhinorrhoea following initiation of CPAP therapy for OSA is very rarely documented in the literature. In this report, we describe a 53-year-old woman with severe OSA who, while being evaluated for possible intracranial hypertension, developed spontaneous CSF rhinorrhoea and CSF aspiration pneumonitis as a complication of CPAP therapy. Magnetic resonance imaging confirmed fluid tracks at the skull base, and a nasal swab demonstrated positive β2-transferrin. Computer tomography (CT) chest showed findings consistent with CSF aspiration pneumonitis. Resolution of both CSF leak and pneumonitis were noted following treatment with azetozolamide and curative endoscopic trans-nasal surgery along with ventriculoperitoneal shunt.