The efficacy of intramedullary fixation for diaphyseal femoral fractures in young patients has been well documented. There is a paucity of data, however, on the efficacy of intramedullary techniques used in the ever growing elderly population. The purpose of this study was to analyze the outcomes and rate of perioperative complications associated with using intramedullary fixation to treat diaphyseal femur fractures in patients older than 65 years. We retrospectively reviewed the medical records and radiographs of 21 patients (17 men, 4 women) with isolated diaphyseal femoral fractures treated with anterograde intramedullary nailing at our institution. All fractures united. Ten surgical complications occurred in 9 (43%) of the 21 patients, and 7 medical complications occurred in 4 patients (19%); overall, 17 medical or surgical complications occurred in 11 patients (52%). Although more than half of the patients had an intraoperative or postoperative complication, intramedullary fixation is an effective method for achieving union in elderly patients with diaphyseal femoral fractures.