The aim of this study is to evaluate the effect of immediate loading on dental implants supporting mandibular complete overdenture in controlled type II diabetic patients both clinically and radiographically. Fourteen completely edentulous males; controlled type II diabetic patients were selected for the study. Their HbA1c (Glycosylated Hemoglobin) level was around 7.  All were examined with pre-operative CBCT (cone-beam computed tomography) to evaluate the future implant site, and for proper selection of implant size. First implant was installed in one side of the inter-foraminal region of the mandible, then after 4 months the second implant was installed in the other side. Two weeks later both implants were loaded by incorporation of O-ring attachments into the existing mandibular complete denture as a direct clinical procedure in the mouth. Both radiographic evaluation of crestal bone loss using CBCT, and clinical evaluation of implant stability using resonance frequency analysis (Osstell device) were made at time of loading, 3, 6, 12 and 24 months after loading. The results showed that after 24 months of loading no significant difference observed between the immediate and delayed loading protocols either clinically (Implant stability), or radiographically (Crestal bone loss). The only significant difference observed in the implant stability between both groups was at time of loading. In this study all clinical and radiographic results suggested that dental implants could be used as a successful and predictable treatment to retain mandibular complete overdentures in controlled type II diabetic patients with a very high success rate either immediately or delayed loaded.