Purpose:This in-vitro study was performed to evaluated stresses applied to the implants retaining mandibular complete overdenture with three different resilient telescopic attachments. Materials and methods:Three identical clear acrylic resin models of completely edentulous mandibular arch were selected for this study. One implant was installed in each canine region of the models by using guide template. The models were scanned to design telescopic attachment using CAD/CAM technology on model 3D virtual image. According to the material of fabrication of the resilient telescopic attachment, the models were categorized as follows: (All Zirconia telescopic group zz) :The primary and secondary telescopic crown were made from ZrO₂ . (All Peek telescopic group pp):The primary and secondary were made from PEEK. (Zirconia Peek telescopic group zp):The primary was made from ZrO₂ and secondary telescopic was made from PEEK. Three identical mndibular complete overdentures were constructed. The secondary telescopic crowns of each group were picked up within the intaglio surface of each overdenture. Four strain gauges were installed on the buccal, lingual, mesial and distal side parallelfor each implant. A unilateral and bilateral load of 70N was applied. The loading protocol was repeated five times for each loading application. Results:In bilateral loading the highest stresses were recorded with PP, followed by ZZ and the lowest stresses were noted with ZP for mesial and buccal sites, while in unilateral loading the highest stresses were recorded with PP, followed by ZZ and the lowest stresses was noted with ZP for all sites. Conclusion:Within limitation of this in vitro study Zirconia Peek resilient telescopic attachment was promised for reduce stress around implants mandibular overdenture.