Purpose: This study was conducted to compare between maxillary implant-supported overdentures retained by telescopic and ball and socket regarding retention. Material and Methods: seven male patients had completely edentulous maxilla free from any systemic disease that might affect bone metabolism was selected to participate in this study. Each patient received four dental implants in the edentulous maxilla using computer guided surgical stent. Implants had enough antero-posterior spread so that load can be distributed equally. Once the implant osseointegration appears to be satisfactory, the maxillary four implants were loaded with two different attachments as follow; Group I: All patients received maxillary single denture retained with ball and socket attachments and used it for three months. Group II: After a wash up period of two weeks, all patients received another newly constructed maxillary single denture retained with telescopic attachments and used it for another three months. Retention of both groups was measured using universal testing machine. The assessment was made at time of insertion, one month and three months follow-up period. Results: Group II showed higher retention values compared to Group I. Conclusion: ball and socket attachment as well as telescopic attachment showed decrease in retention but telescopic attachment revealed a higher score than ball attachment due to frictional retention.