1. The Küntscher method of intramedullary reaming and nail fixation was applied to thirty-five cases of non-union of the lower extremity, twenty femurs and fifteen tibias. A bone graft was generally not used. 2. Most of the patients were allowed to bear weight and to exercise the joints within a few days of the operation. Additional measures such as pre-operative surgery for infection or distraction of shortening were used in some cases. 3. The pseudarthrosis healed in all cases, even when infection was present. The nails were generally not removed until after healing had occurred. 4. It is concluded that the Küntscher method gives remarkably rapid consolidation and restoration of function even in difficult cases of non-union of shaft fracture, particularly of the femur.