Objectives: Spontaneous CSF otorrhoea appears to be an emerging clinical entity. The aetiology, characteristics and treatment outcomes of these group of patients are poorly described so we aimed to further investigate this growing cohort. Methods:A retrospective review of 30 patients with spontaneous, non-iatrogenic, and non-traumatic spontaneous CSF otorrhoea was performed over a five-year period. Baseline demographics, presenting symptoms, past medical history, clinical examination, investigation (biochemical and radiological), management and outcomes were recorded. Result:The majority of patients were obese females presenting with a unilateral middle ear effusion and conductive hearing loss. Beta trace protein sampling of the fluid was positive for CSF for all patients. The most frequent site of leak was at the tegmen mastoideum and middle cranial fossa repair was the most commonly performed procedure with good outcomes. Only one patient had confirmed benign intracranial hypertension. Two patients presented with meningitis which was thought to be due to the CSF leak. Conclusion:Spontaneous CSF otorrhoea should be suspected in unilateral middle ear effusion of unknown cause. Clinical or radiological diagnosis alone appears inadequate in diagnosing a spontaneous CSF leak unless clinicians have a high index of suspicion. This entity appears to occur in the absence of raised intracranial pressure and further studies to elucidate the cause are required.