The present study was designed to compare between the effects of conventional flap implant insertion versus computer guided flapless implant insertion protocols for immediately loaded implants supporting mandibular overdenture prostheses both clinically and radiographically. This study was conducted on fourteen completely edentulous male patients selected from the Outpatient Clinic of the Faculty of Oral and Dental Medicine, Cairo University. The fourteen completely edentulous patients were divided into two groups: Group Ι patients received mandibular overdentures supported by two immediately loaded implants in the canine region following conventional flap technique while Group II patients received mandibular overdentures supported by two immediately loaded implants in the canine region following computer guided flapless technique. Clinical evaluation was carried out for implant stability using resonance frequency analysis immediately after implant installation then after three and six weeks and three, six, nine and twelve months. Also gingival index and clinical attachment level using graduated pressure-sensitive probe were evaluated at the implants installation then after one, two, three and six weeks and three, six, nine and twelve months. Radiographic evaluation for bone height and bone density changes around the implants by using digital periapical radiographs was done at the time of implant installation, three, six and twelve months later. According to the results of this study, implant stability quotient (ISQ) showed a decrease three weeks after implant installation followed by an increase from the third week to the end of the follow up period for both groups. However, the flap group showed statistically significant lower ISQ values. The changes in clinical attachment level (CAL) were statistically insignificant with time for both groups. Comparing the two groups, Group II showed statistically significant less CAL measures. The gingival score values showed statistically significant change with time for group I while group II values were statistically insignificant with time. Comparing the two groups, the measurements of group II were significantly lower than group I. Bone height measurements showed statistically significant increase with time for group I while it was statistically insignificant for group II. Comparing the two groups, bone height changes in group I showed statistically significant decrease compared to group II. For the bone density, measurements were statistically insignificant with time for group I while statistically significant for group II. Comparing the two groups, bone density changes in group II showed statistically significant increase compared to group I. Conclusions • Implants can be successfully inserted using computer guided flapless technique and immediately loaded in case of implant supported mandibular overdentures • The computer guided flapless technique has a positive influence on implant stability which is an important factor for the success of immediate implant loading. • The computer guided flapless technique is a satisfactory procedure as it decreases treatment time and patient discomfort.