All of the current modalities have a place in the treatment of diaphyseal humeral fractures. Functional bracing renders a high rate of union and seems to be a safe method of treatment for most closed fractures. Type II and III open fractures seem to respond best to plate fixation or external fixation, particularly when there are associated neural or vascular pathologic findings. Patients with polytrauma who are unable to walk are also best treated with plate fixation. Plate fixation is also the best method of treatment when adequate alignment cannot be obtained with nonsurgical methods. Intramedullary nailing remains controversial because its complication rate is higher than that associated with either plate fixation or functional bracing. None of the treatments described is a panacea, and complications may occur with each one of them. An appropriate appreciation of the biologic response to the three modalities; an understanding of the indications, contraindications, and possible complications of the treatments; and a mastery of the techniques of application are essential for the attainment of satisfactory clinical results.