The purpose of this paper is to discuss the treatment of pseudoarthrosis of the humerus. The results of 5 cases operated on from 1982 to 1988 were presented and analyzed. Of all the cases, 3 cases had the nonunion in the middle third of the humerus and 2 in the proximal third. For the initial treatment, 3 cases were treated conservatively and 2 operatively. Of the former cases, one case had the good result at the first operation but the other cases were reoperated. The one case underwent a second procedure and the other case underwent a third procedure before healing. Of the latter cases, one case healed with one operation and the other case required a second procedure. Finally, all cases had the good results.