Purpose: The objectives of this study were to evaluate: (1) the clinical outcome of fresh frozen human allogeneic bone grafts (FFB) used for the reconstruction of severely atrophied edentulous ridges; (2) the survival rate of implants placed in the reconstructed areas; and (3) bone resorption. Materials and Methods: During a 2-year period, 19 patients with severely atrophied partially or totally edentulous ridges who were candidates for an implant-supported prosthesis were consecutively enrolled and reconstructed with FFB iliac blocks. Five to 7 months later, 117 implants were placed in the reconstructed areas, and prosthetic rehabilitation was started 5 to 6 months afterward. Results: The mean follow-up of patients after prosthetic loading was 27 months (range, 20 to 32 months). Prior to implant placement, graft exposure with partial or total loss of the graft occurred in four patients. After implant placement, bone graft exposures with partial loss of the grafts occurred in nine patients; in two patients, both grafts and implants were removed. The cumulative survival rate of implants was 90.2%. The mean (± standard deviation) graft resorption before implant placement was 0.98 ± 0.77 mm (range, 0 to 4 mm), while these values were 1.21 ± 1.05 mm (range, 0 to 6 mm) at loading, 1.55 ± 1.57 mm (range, 0 to 8 mm) at 12 months, and 1.93 ± 1.38 mm (range, 1 to 9 mm) at 24 months. Conclusion: Within the limits of this study (limited sample of patients and short follow-up), the reconstruction of severely atrophic edentulous ridges with FFB is associated with a relevant incidence of bone exposures and partial or total loss of the grafts, which may compromise the long-term survival of implants placed in the reconstructed areas. Schlagwörter: allogeneic grafts, atrophy, bone graft, dental implant, fresh frozen allogeneic bone, reconstruction