Purpose: This in-vitro study was performed to evaluate the peri-implant strains with two vertical and two tilted posterior implants supporting a locator retained mandibular over dentures. Materials and Methods: This in-vitro study was carried out on two 3-D mandibular edentulous modelsand auto-polymerzied soft liner material was covered ridge. Four implants were installed into canines and premolars regions bilateral.According to the orientation of the second premolar implants, the models were be classified into two groups. I (control) Second premolar implants were inserted parallel to the anterior implants and perpendicular to the occlusal plane. II (test) Second premolar implants were inclined posteriorly to make a 30^o distal implant inclination from vertical plane. Thentwo mandibular ovedentures were constructed and pick up of attachment were occurred. After that Linear strain gauges were bonded to buccal and lingual sides of each implants sides. By using universal testing machine Unilateral loading for both sides and Bilateral were applied. Results:For parallel group at buccal loading and lingual loading site only, canine implants recorded significant higher strain than premolar implants.  For inclined group at buccal loading and lingual non loading site, premolar implant recorded significant higher strain than canine implants while at lingual loading site canine implants recorded significant higher strain than premolar implants. Conclusions: Within limitation of this in-vitro study, it could be concluded that: Distal inclination of premolar implants used to support 4 implants retaining overdenture with locator attachments is preferred than vertical implant placement as it reduce stresses to peri-implant bone areas secondary to shortened cantilever length of overdenture saddles Key words:Implant overdenture, locators attachment, inclined implant, stress analysis.