Purpose: To retrospectively evaluate the 1-year outcome of implant therapy involving localized lateral alveolar ridge augmentation with block bone grafts, and to compare outcomes of implants inserted simultaneously with grafting or after a healing period. Materials and Methods: Consecutively treated patients undergoing alveolar ridge augmentation with autogenous intraoral block grafts before or simultaneous with implant placement between 2005 and 2010 in the Oral Surgery Unit of the University of Valencia were included. The selection of procedure (simultaneous vs delayed implant placement, donor site) was based upon the criterion of the surgeon and thorough evaluation of each patient. All grafts were obtained with piezosurgery. Complications related to augmentation, implant survival, implant success, and peri-implant marginal bone loss were assessed. Results: Forty-two patients were included; 45 sites were augmented and 71 implants were inserted (33 delayed and 38 simultaneously). Complications (temporary paresthesia, wound dehiscence with bone graft exposure, and exposure of osteosynthesis screw) occurred after bone harvesting in nine patients; four were in the simultaneous group and five were in the delayed group. Six grafts were not successful; four were lost and two provided insufficient bone (after resorption) for ideal implant placement. The implant survival rate was 98.5% (100% for simultaneous and 96.9% for delayed implants) and the implant success rate was 92.9% (89.5% for simultaneous and 96.9% for delayed implants). Average marginal bone loss 1 year after loading was significantly higher for simultaneously placed implants (0.69 ± 0.67 mm) than for delayed implants (0.20 ± 0.50 mm). Conclusions: In lateral bone atrophy, block bone grafts provided sufficient bone for implant therapy, with few complications. Both simultaneous and delayed implant placement yielded high implant survival and success rates. Average marginal bone loss was significantly higher around simultaneously inserted implants.