Endoscopic sinus surgery (ESS) is a standard treatment for rhinosinusitis, which failed optimum medical therapy. Iatrogenic cerebrospinal fluid (CSF) rhinorrhoea can occur during ESS warrants early repair of the leakage. The common sites for CSF leakage are cribriform plate, fovea ethmoidalis, and anterior ethmoid sinuses. We present five cases of iatrogenic CSF rhinorrhoea due to ESS and its management.