Objective: The purpose of the present study was to evaluate the effect of different types of attachments on the maximum biting force in patients wearing implant retained mandibular overdentures. Materials and Methods: Ten completely edentulous patients participated in this study. Patients were rehabilitated with two implant retained overdentures. Patients were divided into two groups. Group (I): Patients had received ball & socket attachment retained implant over-dentures. Group (II): Patients had received bar attachment implant retained overdentures. Implants were installed in the mandibular canine areas in both groups. Implants were left buried till complete Osseo integration, ball or bar attachments were then attached to the implants. The mandibular overdentures were fitted onto the attachments via direct pick-up technique. The Maximum Biting Force (MBF) was evaluated by using Load star sensor device placed in the premolar-molar area of the denture. Patients were instructed to bite hard on load sensor, the MBF values were displayed on a computer display connected to the device. Results: The MBF of both groups increased gradually by time. However, patients of GP (I) had shown statistically non-significant higher MBF values than Gp (II). Conclusions: The MBF of patients with ball and socket or bar attachment implant retained overdentures had been increased throughout the follow-up period. Group(I) had recorded non-significantly higher MBF values than Group (II)