Objectives: Immediate functional loading considered an advantage reducing time , cost and second surgery time. Implant design plays a great role to enhance osseointegration ; providing an additive. Aim of this study is evaluating the results of an immediate functional loading in single mandibular posterior region. Methods: - Sixteen patients with very restrict inclusion criteria including bone quality , bone quantity and bone angle - All patients evaluated by CBCT to identify the selection criteria - Eighteen implants ( Kontact ®Implants, BIOTECH international)were received according to surgical protocol - All implants inserted with insertion torque more than 35 N. - All patients received straight nano post abutments and definitive restoration within 48 hours post implant insertion - Radiographic evaluations were performed at the base line and after year to evaluate crestal bone level - Three measures were obtained for each implant ; implant length at midaxis and mesial and distal crestal perpendicular bone lengths to the apical end of the implants ( used as reference point ) - Mesial and distal crestal perpendicular bone results were standardized with the known midaxis implant length - Mesial and distal bone lengths were then averaged and the mean bone level change was computed. Results: - Seventeen implants were clinically successful , one implant failed due to infection , yielding a success rate of 95 % - The radiographic crestal bone levels were expressed in millimeters from the top of implant platform to the first bone to implant contact - The radiographic analysis reveals the mean crestal bone level change for one year was - 0.45 mm ± 0.10 mm. Conclusion: With the limitations of this study concerning the sample size ; this prospective study indicates that immediate functional loading protocol can achieve a clinically predictable outcome with respect to restricted inclusion criteria of the patients. Palabras clave: immediate functional loading, immediate loading, loading protocol