From January 1987 to April 1993, 25 multiply injured patients were treated with closed intramedullary Ender nail fixation of the humeral shaft. Criteria for the procedure were humeral diaphyseal fractures with associated multiple injuries. Seventeen distal and mid-shaft fractures were treated via a modified anterograde approach in which the rotator cuff is not violated. Eight proximal third fractures were treated via the standard retrograde approach. Postoperative follow-up averaged 36 months. Full range of motion was attained 17 of the 25 patients. Of the eight remaining patients, three with a slightly limited range of motion achieved full range of motion following nail removal; three had preoperative radial nerve palsy which resolved within 1 year, and two patients required follow-on plating. In 92 per cent (23 of 25) there were no incidences of infection or non-union. Flexible nails avoid complications of reaming. The modified anterograde approach allows excellent shoulder motion since it does not violate the rotator cuff. Ender nails provide excellent fixation and clinical outcome in the multiply injured patient and are cost effective compared with interlocking nails.