Purpose: The aim of this study was to assess the clinical status and radiographic and densitometric peri-implant tissue changes as parameters for the success or failure of 40 mandibular implants supporting intracoronal mandibular Kennedy Class I removable partial overdentures in a 2-year prospective study. Materials and Methods: Twenty consecutively treated men who received mandibular implants bilaterally to support an intracoronal Kennedy Class I removable partial overdenture were selected. Plaque and gingival bleeding indices, probing pocket depths, marginal bone loss, and bone mineral density were recorded. Bone loss and density were assessed through intraoral periapical radiographs and dual-energy x-ray absorptiometry, respectively. Data were recorded at the time of overdenture insertion and 6, 12, 18, and 24 months later. Results: Two implants failed, resulting in a success rate of 95% after 24 months. The plaque and gingival bleeding indices changed significantly between the different observational periods. Within the physiologic limit, there were detrimental effects on both marginal bone levels and probing pocket depths. Meanwhile, the bone mineral density around the implants increased significantly in a time-dependent manner. Conclusion: Within the limitations of this study, mandibular implants supporting an intracoronal Kennedy Class I removable partial overdenture can be recommended as a viable treatment modality for rehabilitation of patients with partial bilateral mandibular posterior edentulism. Keywords: bone density, clinical indices, Kennedy Class 1, implant-tooth-supported removable partial overdenture, radiography