The records of twenty patients who had been treated for a non-union of the distal end of the humerus at the Massachusetts General Hospital from 1968 to 1984 were reviewed. Thirteen of the fractures were extra-articular and seven were intra-articular. Seven fractures had been open and nine had been associated with multiple trauma. Eight had been initially treated by open reduction and internal fixation; five, by closed reduction and immobilization; four, by skeletal traction; two, by external fixation; and one, by debridement and immobilization. The average time from the original fracture to the treatment of the non-union was twenty months (range, three to 120 months). All but one patient had pain and instability, and fifteen (75 per cent) had limited motion of the elbow. Radiographically, eleven were considered to have a reactive non-union and nine, a non-reactive non-union. Seventeen (94 per cent) of the eighteen non-unions ultimately united. Two patients underwent excision of the distal end of the humerus and replacement with an allograft. At follow-up (average, 3.6 years), function in one patient was rated as excellent; in six, as good; in seven, as fair; and in six, as poor. The patients who had an extra-articular supracondylar non-union had the best over-all results, while those who had a non-union that was associated with an intra-articular component or severe soft-tissue trauma did less well. It should be emphasized, however, that most of the patients in this study continued to have a major long-term disability, despite the fact that union was successful.