Purpose: of this present study is to compare between 2 different treatment modalities of conventional implant and mini-implant supported overdenture using EMG analysis for 3 months period. Materials and methods: Fourteen completely edentulous patients were selected from the outpatient clinic of the Prosthodontics Department, Faculty of Oral and Dental medicine, Cairo University according to certain criteria. For all patients, conventional complete denture was made as usual. After proper adjustments of the dentures patients were divided into two equal groups, 7 patients in each group. For first group each patient will receive two-implant fixture with ball attachment in the mandibular canine region, which will be immediately loaded with mandibular overdenture and second group each patient will receive four mini-implants placed in anterior area of the lower dental arch and will be immediately loaded with mandibular overdenture. Patients were recalled after two week; one month, 2 months and after three months from wearing the dentures for electromyography evaluation. The muscular activity measurements were done during clenching. Results: Statistical analysis of collected data in two groups separately and a comparison between the two groups together was done. The results obtained from this study revealed that, a statistically significant difference in muscular activity between immediately loaded conventional implant and mini-implant supported mandibular overdenture and it was revealed from the attained results that the conventional implants provided better muscular activity than mini-implants throughout the study periods.