Visor osteotomies of various designs, supplemented with illiac bone grafts, were used to augment 63 cases of severely atrophic mandibles. The rate of resorption measured on lateral cephalograms was 28% after four years, with the best performance by the full visor with peripheral bone graft (PA), and the worst by the short visor with onlayed bone graft posteriorly (PO). Ridge forms were usually inverted V-shaped or inverted U-shaped, but occasionally comma-shaped, the best form for providing retentive qualities for the denture. Only 39% were free of neurosensory problems. It was concluded that indications for such a procedure should be viewed in the light of frequent nerve injuries, adverses patterns of resorption for denture retention and newer and more effective methods for ridge augmentation using hydroxylapatite.