Retention and stability are problems of the mandibular prosthesis causing complain of complete denture wearers.Mandibular implant over denture is a successful treatment in this group of patients. The occlusal scheme is an important factor in the design of complete dentures, the occlusal philosophies that are proposed for implant overdentures are based on those for conventional complete dentures. Two occlusal concepts exist in complete denture treatment: bilateral balanced occlusion and canine guidance both include simultaneous contact in centric occlusion, but they differ in eccentric movements. Materials and Methods: Six completely edentulous male patients since two years ago were selected according to some criteria, each patient was received upper and lower complete dentures with bilateral balanced occlusion, then each patient was received two root form implants at the canine area, then the same patient`s mandibular denture was modified to the overdentur, after the adaptation period exchange of the occlusal scheme and the recording procedures were made.   Results: Improved biting force and masticatory efficiency with implant retained mandibular overdenture, high values of biting force with bilateral balanced occlusion, better values of masticatory efficiency(less time &number of strokes) with canine guidance occlusion.   Conclusion: Improved biting force and masticatory efficiency with implant retained mandibular overdenture. The bilateral balanced occlusion in case of biting force has maximum biting force value than canine guidance occlusion .The canine guided occlusion in case of masticatory efficiency has less time and number of strokes than bilateral balanced occlusion.