In order to document functional outcome, we followed fourteen patients who had an injury of the sciatic nerve associated with a displaced acetabular fracture for a mean of twenty-seven months. In three of the patients, the injury was iatrogenic. Electromyography was useful in the localization and determination of the severity of the injury. According to the functional scale that was used, all but one patient had a satisfactory (fair or better) functional outcome, but eleven patients had residual neurological sequelae that ranged from minor paresthesia to footdrop. Seven patients who had an injury of both the tibial and peroneal divisions of the sciatic nerve had complete or nearly complete motor and sensory recovery of the tibial component. The patients who had isolated, mild involvement of the peroneal nerve had a favorable prognosis, but those who had a severe injury of the peroneal component, whether it was isolated or associated with an injury of the tibial component, did not recover good function.