Objective : The purpose of this paper is to evaluate diagnostic value of cone beam CT for pre-surgical assessment of implantation.. Methods : CT images which produced by i-CATTM system reformatted using SimplantTM (Materialise, Belgium) or VimplantTM (Cybermed, Korea) software tools. And usefulness of cone beam CT was evaluated according to the imaging goals for implant site assessment by case studies. Results : 1). Images which produced by CBCT can be used to determine status of the anatomy in the proposed implant site and how to best optimize the implantation considering anatomic constraints. 2). Images allow to accurate measurement of remaining bone height and width easily. 3). Images reveal cross-sectional bony architecture and therefore can be used to estimate bone density. But bone density value produced by i-CATTM system does not correspond to CT number. 4). SimplantTM or V-implantTM software tools provide the function simulating implatation on the reformatted volume images. It was very useful to determine implant position or orientation. Conclusion : Images which produced by cone beam CT was very valuable to identify internal anatomy, to estimate bone quantity and quality and to determine implant position and orientation for pre-surgical assessment of imlantation.