We treated 19 patients with established nonunion of the radius and/or ulna by the excision of avascular bone and the grafting of blocks of corticocancellous bone from the iliac crest, augmented by rigid plate fixation under compression. This allowed early mobilisation, and bony union was achieved between three and 24 months after operation in all but one of the patients. The single failure was attributed to the excessive length of the defect (100 mm) and inadequate fixation.