Cerebrospinal fluid (CSF) rhinorrhoea is leakage of fluid from the subarachnoid space to the frontal, sphenoidal or ethmoidal sinuses, and may occur spontaneously. The authors present the first reported case of bilateral spontaneous CSF rhinorrhoea. Bony defects on both sides of the cribriform plate were identified using endoscopic and radiological techniques, and the CSF fistula was closed endoscopically. The aetiology, diagnosis and contemporary surgical treatment of spontaneous CSF leaks is discussed. Endoscopic repair was successful in this case, and in view of the high success and low reported complication rates this surgical approach should be considered for treatment of spontaneous CSF rhinorrhoea.