Endoscopic sinis surgery has emerged in the last decade as the treatment of choice for chronic sinusitis. Although the overall complication rate for an experienced surgeon is low, the potential complications may be severe. Cerebrospinal fluid rhinorrhea(CSF) occuring during endoscopic sinus surgery is rare, but may be lead to intracranial complications if it occurs. Surgical repair of CSF rhinorrhea can be made through either an intracranial or extracranial approach. The initial surgical treatment of all CSF rhinorrhea should be undertaken through extracranial rhinologic approach because of less possibility of morbidity and anosmia. A variety of techniques have been reported for this extracranial approach using septal mucosal flap, turbinate mucosal flap or free fascial graft via extracranial approach. This report describes our experience of the iatrogenic CSF rhinorrhea in a patients who previously received endoscopic sinus surgery. We used a inferior turbinate osteomucoperiosteal graft successfully at the first attempt in the management of a large defect(1.8×0.7cm), which developed over the right fovea ethmoidalis and lateral lamella of the cribriform plate.