The present study was conducted on twenty two partially edentulous patients selected from the outpatient clinic of the Prosthetic Department, of Faculty of Oral and Dental Medicine, Cairo University.Patients were divided into two groups; each group received two implants in the distal extension area with ball attachments in one group and locator attachments in the other group. Both groups were then restored with implant retained mandibular partial over denture.Retention of the prosthesis in both group, was evaluated at the time of delivery of prosthesis and three months later using digital force gauge.The result of this study showed significant difference in the retention values between the prosthesis retained with ball and socket and that retained with locator in favor to the locator attachment where the retention value are much more higher in the prosthesis retained with locator.