Background: Cerebrospinal fluid (CSF) is a clear watery nutrient-rich fluid that circulates around through the brain and spinal cord. CSF rhinorrhoea is the drainage of that fluid into nose. It is a symptom of failed containment of CSF to its subarachnoid space. Treatment of CSF rhinorrhoea includes medical treatment and surgical. Aim of work: This study aims to evaluate the use of endoscopic transnasal repair of this leak through four layer technique. Material and Methods: This study was conducted on 20 patients. C.T cisternography using Omnipaque were done for all patients. Injection of Flourescine intra-thecaly was done pre-operatively. Results: 18 patients were completely cured from the CSF leak. One patient needed to be re-apenated againe to stop the CSF leak. One patient developed meningitis 1 month after surgery, still no CSF leak so 19 patients stopped leaking (95% success rate). Conclusion: CT with intra-thecal injection of Omnipaque is reliable for diagnosis and determinations of the site of the leak. Pre-operative intra-thecal injection of Flourescine offer the advantage of clear exact identification of the site of the CSF leak. Recommendations: Trans-nasal endoscopic repair of CSF rhinorrhoea through the 4-layers technique with the aid of Flourescine is a successful safe technique with minimal complications.