Of 46 patients, 30 with fresh fractures of the humerus, nine with non-unions and seven with pathological fractures were treated with a new locked intramedullary nail. Of 30 patients with a fresh humeral fracture, three were lost to follow-up. All fresh fractures healed within 4 months. Functional results of the fresh fracture group were excellent in eighteen patients and satisfactory in three patients. Two patients with Neer type 6 fractures had unsatisfactory shoulder function; in the four other patients poor shoulder function resulted from a pre-existing condition. Out of nine non-unions, six united within 6 months. The three other patients with atrophic non-union required bone-grafting later, after which consolidation was obtained. The long functional recovery period of the non-union group was related to the pre-existing limited shoulder function. The seven patients with a pathological fracture died within 8 months of operation. While alive they were free from pain and could be nursed well.