A number of grafting materials have been used in vertical and horizontal ridge augmentation to enable implant placement in optimal positions. Autogenous block grafts from intraoral or extraoral sites have been used with positive results. Allograft blocks with cortical bone are also used for ridge augmentation. In this case series, cancellous allograft blocks were used for horizontal augmentation of the maxilla. The observed increase in ridge width allowed subsequent implant placement after a 5-month healing period. Four months after placement, the implants were uncovered and restored. The results suggest that cancellous block allografts may be a viable alternative to autogenous block grafts or cortical allograft blocks in treatment of deficient maxillary alveolar ridges to allow subsequent implant placement in optimal position in the maxilla.