Although rare, non-union of femoral shaft fractures is a cause of significant morbidity. In aseptic non-union, excellent union rates have historically been reported following reamed exchange femoral nailing. However, recently, a high incidence of failure requiring additional procedures has been reported. In light of these concerns and a recent change in our practice to the use of thin solid nails we undertook a retrospective study to determine the efficacy of exchange nailing with these modern nails in our hands. We reviewed records and radiographs of 25 patients who had a reamed exchange femoral nailing for established aseptic non-union. 24 patients (96%) united after exchange without the need for an additional procedure. The mean time to union was 29.75 weeks. Patients who had open bone grafting performed at the same procedure tended to unite quicker, but this did not achieve statistical significance (p = 0.14). Union times were not affected by smoking habits or nail type. This study demonstrates that reamed exchange nailing for aseptic femoral non-union remains an effective treatment. We believe that the nail type is less important than the biological effects of reaming, bone grafting and dynamization.