Fahmyzarzoura, Dr. Ahmed Khalifa*, Prof. Salah AbdElfatTahHegazy**.^. : The aim of this study: was to evaluate of the retention of ball attachment in comparison to locator attachment used to retain mandibular three-implant assisted overdentures through time intervals. Material and methods: six completely edentulous patients were received three implants assisted mandibular over denture retained by ball attachment and locator attachment. Result: there was statistically significant difference between locator attachment and ball attachment with higher retentive values recorded for locator attachment. Conclusion: Retentive values of locator attachment are maintained in the first three months after insertion. However ball attachment did not maintain the same retentive values in the same period.