NouraNuri  Aga¹, MoustafaAbdouELsyad² ,Ahmed Ali Habib^{3. 1}BDS, Faculty of Dentistry, Tripoli University, Libya. ²BDS, MSc, PhD, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. ³ BDS, MSc, PhD, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. Abstract: Objectivesthis study aimed to examine the retention of different types of locator and resilient telescopic attachments for two implant retained mandibular over denture. Methods:An acrylic resin model of an edentulous mandible without alveolar undercuts was fabricated and 2 laboratory implants were inserted in the canine areas. Mucosal simulation was fabricated over the model. Mandibular experimental overdenture were constructed over the model and connected to the model with either resilient telescopic attachment (group I) or Locator attachment (group II). The universal testing machine was used to apply vertically oriented 4 points tensile loads on a metal plate attached to the model with 4 metal chains until the attachments separated from the abutments. Maximum load needed to dislodge the experimental overdenture from the mandibular test model (retentive force) were calculated. Intial retentive forces and retentive forces after repeated insertions and removals were calculated.  Results:For initial retentive forces and retentive forces after repeated insertions and removals, Locator transparent recorded the highest retentive forces, followed bylocator pink, locator blue and the resilient telescopic recoded the lowest retentive forces Conclusions:Locator transparent recorded significant higher retention forces compared to other types of locators and telescopic attachment. The lowestretention was recorded with resilient telescopic attachment. Keywords: Locator, telescopic, attachment, retention, implant overdenture