To investigate the injury mechanism in patients who had peroneal neuropathy after a tibio-fibular fracture and the correlation between tibio-fibular fracture location and the severity of the peroneal neuropathy by using electrodiagnosis.Thirty-four patients with peroneal neuropathy after a tibio-fibular fracture were recruited for this study. Their medical records, radiologic and electrodiagnostic findings were investigated retrospectively. They were divided into 2 groups according to the existence of a fibular head fracture. The group of patients without the fibular head fracture was further classified according to the criteria of Orthopedic Trauma Association (OTA) classification. The differences between the two groups in the severity of the neuropathy and electrodiagnostic findings were evaluated.Nine cases (26.5%) had tibio-fibular fractures with a coexisting fibular-head fracture and 25 cases (73.5%) had tibio-fibular fractures without fractures in the fibular-head area. There was no statistical significance in the correlation between the existence of the fibular head fracture and the severity of the electrodiagnostic findings. Neither was there any statistically significant relationship between the site of the tibio-fibular fracture and the severity of the peroneal neuropathy (p>0.05).This study showed there were numerous cases with common peroneal neuropathy after tibiofibular fracture without a coexisting fibular-head fracture, which shows the importance of indirect nerve injury mechanisms as well as that of direct nerve injury as a cause of peroneal neuropathy. In addition, this study showed that there was no statistically significant correlation between the site of tibio-fibular fracture and the severity of peroneal neuropathy.