The aim of this study was to compare the stress patterns induced by ball attachments and locator attachments when used to retain mandibular overdentures supported by either two or four root form dental implants using Finite Element Analysis. Four 3D finite element models were created simulating clinical situation where an edentulous mandible was restored by four different treatment options using implant overdentures. The overdentures were supported by either two implants placed at the approximate canine region or four implants; two at the approximate canine region and other two implants at second premolar region using ball and locator attachments. The models’ components were created on commercial CAD/CAM package then imported to Finite Element Software. The load was applied of value of 100 N and was applied at angle o of vertical 90 then oblique 110° lingu-buccal direction on the region of the right premolar/molar area. The results of this study showed that the stresses generated by the application of vertical or oblique loads varied according to the type of attachment connected to the implant and to the number of implants used to support the overdenture. Keywords: Dental Implants, Locator attachment, Ball attachment, Finite Element Analysis.