Objective: Fibrous dysplasia (FD) is an unusual developmental abnormality of the skeleton. When facial and cranial bones are involved in FD, it is termed craniofacial fibrous dysplasia (CFD). Although several reports have reported that CFD has a tendency for spontaneous cerebrospinal fluid (CSF) leakage, there have been no related English-language case reports. We present the first case of post-traumatic CSF rhinorrhea associated with CFD. Methods:A 30-year-old man presented with CSF rhinorrhea after a mild head trauma. Computed tomography cisternogram located a defect in the posterior wall of the right frontal sinus. Imaging examination also showed the evident expansionof multiple skull bones, spinal scoliosis, and multiple local enlargements of ribs. Without café-au-lait cutaneous spots and endocrine abnormalities, polyostotic FD was diagnosed instead of McCune-Albright syndrome (MAS). The patient underwent craniotomy fistula repair surgery. The excised bone was contoured to be thinner to increase the cranial cavity. The patient recovered well and CSF leakage did not recur. But during a nineteen-month follow up, sight in the patient’s left eye was decreased. MAS was suspected. Unfortunately the patient refused to take the proposed decompression surgery and laboratory tests of serum hormones. Conclusions: CFD, if the wall of the paranasal sinus is involved and the cranial cavity is decreased, may increase the risk of CSF rhinorrhea after head trauma. Expectant management is recommended in asymptomatic CFD patients even in the presence of optic nerve compression. As MAS may cause more problems, it should be precluded before polyostotic FD is diagnosed.