PURPOSE: Sensory impairment in infraorbital nerve is common symptom following mid-facial fractures. The purpose of this study is to document the incidence of sensory impairment in infraorbital nerve following mid-facial fractures and its recovery. METHODS: Three hundreds fourteen patients with mid-facial fracture were included involving emergence areas of infraorbital nerve. Fractures were classified into zygoma fracture, maxilla fracture, complex comminuted fracture and pure blow out fracture. Neurosensory function was assessed with clinical symptoms and light touch test in infraorbital nerve regions. Patients were followed and sensory function was evaluated immediately, 1, 3 and 6 months after trauma. RESULTS: The total series consisted of 198 zygoma fractures, 19 maxilla fractures, 30 complex comminuted fractures and 67 pure blow out fractures. The incidence of sensory impairment was 60% (63% in zygoma fractures, 84% in maxilla fractures, 93% in complex comminuted fractures, 31% in pure blow out fractures). Persistent sensory impairments were remained in 32% (33% in zygoma fractures, 47% in maxilla fractures, 73% in complex comminuted fractures, 6% in pure blow out fractures) 6 months after trauma. Younger patients had better prognosis than older patients in recovery of infraorbital nerve function(p<0.05, chi2-test). Mean recovery time was 11 weeks. CONCLUSION: The incidence of post-traumatic sensory impairment was different according to fracture types. Age of patients and fracture type were important factors that influence to recovery of sensory impairment. Complex comminuted fracture had poor prognosis, and pure blow out fractures had better prognosis than other fractures.