Mohammad SaadALRajehi¹, Ali Hamed EL-Shoukouki², Ashraf Anwar Gebreel³ 1.BDS faculty of dentistry 6 october university 2. Professor of Removable prosthodontics 3. Lecturer of Removable prosthodontics   Abstract: Background: The passive fit is an important factor to reduce the loading on the implant/abutment and supporting bone structure and to maintain mechanical and biological equilibrium. Ill-fitting prostheses may be created stresses which cause some compaction bone and implant. Aim of study: The In-vitro study was conducted to test and compare stress transmission character on abutment of vertical misfit of bar framework of overdenture on implant abutment versus horizontal misfit. Materials and Methods: The in-vitro study was carried out on acrylic resin model representing mandibular completely edentulous and silicone auto-polymerized soft liner material that covering residual ridge and retro molar area was prepared. Then the Hader bar was fabricated which connected two pairs of dummy implantswere inserted in canines regions in acrylic resin model. The four strain gauges were applied to each implant. Eighteen frame works with misfit were prepared. According to thickness and direction of misfit, the frame works were divided into two main groups. Group A: nine frame works with different levels of horizontal misfit (0.1, 0.2 and 0.3). Group B: nine frame works with different levels of vertical misfit (0.1, 0.2 and 0.3), after that, the overdentures were prepared. Finally the load was applied by using UTM. Data was collected and statistically analyzed. Conclusion: Within the limitation of this in-vitro study design, the following conclusions could be drawn: There was statistically significant different of vertical misfit and horizontal misfit at 0.1,0.2and 0.3mm 0.05 level of significant along MD direction and LLing direction for both side right and left in anterior region and at posterior region.