PURPOSE OF THE STUDY: Although aseptic non-union of humeral shaft fractures is generally considered to be an exceptional complication, rates in the literature have varied from 1 to 10%. Factors favoring non-union are often related to technical error or inappropriate therapeutic indication. Several types of treatment (orthopedic, locked centromedullary nailing, ascending pinning, plating, external fixation) can be proposed for humeral shaft fractures. In all cases, a precise technique and proper indication are essential for success. We reviewed the cases of 30 patients who underwent surgery for aseptic non-union of humeral shaft fractures between 1995 and 2000. MATERIAL AND METHODS: Mean patient age was 43 years. Oblique and transverse fractures of the middle third of the shaft predominated. All types of treatment had been used but most of the patients had had ascending pinning. All patients were treated with plate fixatin and a cancellous bone graft after identifying the radial nerve. RESULTS: Bone healing was achieved in all patients. Mean delay to healing was 16 weeks with good motion of the shoulder (mean elevation 136 degrees ) and elbow (mean motion 10-130 degrees ). Transient radial paresia recovered spontaneously in two patients. There was one infection. Only two patients complained of a painful arm that was not bothersome for daily activities and did not require long-term analgesia. There were no cases of radial nerve injury. Elbow function improved in 16 patients, was unchanged in 11, and showed limited extension in 3. Shoulder function improved in 15 patients and was unchanged in 15. DISCUSSION: Plate fixation is widely described in the literature for the treatment of humeral non-union. The main complications of this treatment are radial palsy and infection, reported in 5% of the series. Several recent reports have therefore advocated locked nailing or external fixation with an Ilizarov device but these techniques are difficult to use and have their own risks of complications. It is difficult to block rotation and the nail may injure the rotator cuff. Pin tract infection, nerve injury, and prolonged external fixation are other disadvantages. We therefore recommend screw plate fixation with a cancellous bone graft. Our good results combined with the very low rate of complications argue in favor of this therapeutic option.