Purpose: This study evaluated the biologic response to titanium mesh and autogenous particulate bone grafts for the reconstruction of segmental mandibular defects in a dog model. Materials and Methods: Unilateral 40-mm critical-sized continuity defects of the mandible were made in five beagle dogs. Titanium mesh was shaped and fixed with titanium screws in the defects. Autogenous bone was harvested from the ablated mandible and iliac crest (the ratio of cortical bone:cancellous bone was 3:1) and used to fill the mesh. Two implants were placed into each bone graft. The animals were sacrificed after 6 months. Radiographs, histologic sections, scanning electron microscopy, and energy dispersive spectroscopy were performed to evaluate bone formation and osseointegration of the implants in the reconstructed mandibles. Results: The outline of the reconstructed mandible was satisfactory, and no bone resorption was observed in the defect area. All implants showed excellent osseointegration of the grafted bone. Furthermore, the density of bone formed around the implants was higher than that seen in control samples (intact, ungrafted dog hemimandibles). Conclusions: Shaped titanium mesh with autogenous particulate bone graft is a predictable method for restoring critical-sized continuity defects of the mandible. Simultaneous implant placement is feasible and the structure of bone formed near implants may be optimal. Keywords: bone graft, immediate implant placement, mandibular reconstruction, titanium mesh