Purpose: to evaluate the retention of two different retention mechanisms (nylon caps and retention sil) in locators retained implant mandibular overdenture. Materials and methods: This randomized control trail was carried on twelve completely edentulous patients who received two mandibular implant in the cuspid region bilaterally with locators abutments. The patients were randomly divided into 2 equal groups at the time of implant loading. Group I: overdentures were pickup with conventional metal housing and nylon caps, Group II: overdentures were pickup with silicone housing retention sil, Forcemeter digital device was used to evaluate the retention of the 2 groups during the follow up period at the time of loading ,three, then six month later. Results: The results revealed that there was a statistical significance difference between the 2 groups with higher retention value for direct pick up metal housing and nylon cap group 1 .While there was no statistical significance difference within each group. Conclusion: Retention sil silicon housing is no longer reliable technique for retaining implant assisted overdenture mandibular.