Aim of study:  The purpose of this in vitro study to evaluate and compare the effect of the Locator attachment with different retentive inserts on the stresses around implant retained mandibular overdenture. Material and Methods:This study was carried out on clear acrylic resin model representing mandibular completely edentulous with Two dummy implants were inserted bilaterally in canine region in each model using consecutive drilling procedure. Then the ridge was covered by auto-polymerzied soft liner material. Locator abutments were secured to dummy implants. Each model was duplicated with dental stone and two overdentures were prepared. According to the different retentive insert two groups were studied Group I clear nylon insert. GroupIIorange nylon insert each group with 1mm height. Each implant was received four strain gauges to measure the axial strain around the implants by used universal testing machine with biting force (70 Newton). Data was collected and statistically analysis. Result: Bilateral loaded gives the least values with orange nylon inserts as it was (28.13), in contrast with clear nylon inserts gives the highest stress as it was (55.12). Conclusion: Within the limitation of this in vitro study orange nylon insert gives the least stress value around implants.