This paper describes onlay graft procedures and discusses the technical considerations involved in one- or two-stage implant placement. The results of a 5-year clinical experience with such procedures are reported. Intra- and extraoral donor sites were used to harvest cortico-cancellous grafts: 25 patients were treated with chin monocortical grafts, 8 patients with monocortical hip grafts, and 18 patients with bicortical hip grafts, depending on the size of the defect and the location of the graft. The monocortical grafts were used in the maxilla, and the bicortical grafts in the mandible. Four months after the surgery, a reentry procedure was performed to place implants in the patients with monocortical grafts, while the implants in the mandibular onlays were placed simultaneously with bone augmentation. CT (computer tomography) and Panorax comparisons were made 24 hours postoperatively; after 4 months for the monocortical grafts only; and after 1, 3, and 5 years to evaluate the bone resorption. The results obtained with the onlay grafts suggest that this is the method of choice for solving different kinds of alveolar and basal jaw bone reabsorption. Either a monocortical bone or a bicortical graft (type 1 or type 2 bone atrophy, respectively) with the osseointegrated fixtures-bone graft combination were found to guarantee acceptable reabsorption of a graft during 5 years and prevented failure of the prosthetic rehabilitation. In monocortical grafts, delayed fixture placement by 4-6 months is the most predictable; the one-stage procedure is preferred for the bicortical hip graft in the mandible.