After years of experience in the treatment of fresh diaphyseal fractures of the tibia and humerus using functional braces, we began to use them in cases of delayed union and pseudarthrosis. This decision was encouraged by the excellent results obtained in fresh fractures and by the favourable effects of function on the repair process. The 15 cases reviewed, 13 in the tibia and 2 in the humerus, had previously been treated by various traditional methods. Treatment by functional bracing consisted of removing any plates or other devices, sometimes in association with "minimal" surgery such as fibular osteotomy, prior to the application of the functional brace. Total weightbearing was allowed ab initio until there was complete radiographic healing. All the cases resulted in complete healing over a period ranging from two to five months, with total functional recovery of the limb involved.