A technique for the transfer of diagnostic information from transaxial CT scans to diagnostic casts is presented. A duplicate of the patient's existing prosthesis is utilized as a custom tray and an impression of the edentulous arch is made. The data from the transaxial radiographs are transferred to the diagnostic cast using anatomical landmarks as reference points. The marked cast can be used by the surgeon and the restorative dentist for optimal implant placement. (Implant Dent 1993;2:97–99)