Surgical reconstruction of mandibular defects is usually considered a challenge. This technique describes a workflow for CAD/CAM fabrication and insertion of PEEK implant for partial marginal resection of the mandibular angle bone for a 17-year-old young female diagnosed with low grade osteosarcoma. High resolution cone beam computed tomography scan was performed for digital planning. 3D rendering based on the DICOM data was performed using Ceramill Mind - software (Amann Girrbach AG), which produced a three-dimensional model of the mandible. The implant was first 3D designed on computer (Ceramill Mind - software), milled into wax and then finally produced using PEEK injection molding technique. The patients' aesthetics and functions regarding speech, mastication, and normal opening without deviation were maintained as detected after 6-month follow-up. Combination between CAD/CAM and use of PEEK material in the reconstruction of mandibular defects could be a promising treatment option to restore the physiologic functions of the mandible.