An in-vitro study was done to compare between splinted and un-splinted Medi-implants and their effect on the implants and supporting structure. Two mandibular acrylic models were made with the placement of two implants in each one on the canine region. Locator and bar were used as attachments. After the attachment was fitted to its abutment four channels were done in each model mesial and distal to the implants to receive the strain gauge. Universal-testing machine was used to apply standardized static load with a special load applicator. Loading was performed unilaterally in vertical direction at right 1st molar on both models. Then a bilateral loading was applied in vertical direction on both models at the 1st molar. Comparing the results of the two types of attachment revealed that there was a significant difference between them (p value<0.001). So, it can be concluded that un-splinted implant retained mandibular overdenture transmit less stress to supporting structures than splinted implants. In both splinted and un-splinted retained mandibular overdenture, the distal aspect shows greater stress than the mesial one.