This Book is carried out combining the concept of ergonomics and biomechanics by designing an intramedullary rod for the fractured human femur bone. Many failures in the human femur implantations are being encountered in post-surgical operations. One of the reasons is the inappropriate selection of the intramedullary rod material, dimensions and its designing. In this project, the ultimate strength of the original femur bone and the femur intramedullary rod are compared and the optimum length, material and optimum diameter of the rod are calculated using the data with respect to the height of 31 female individual humans. The optimization process is carried out using RANDOM SEARCH METHOD which is a type of non-gradient, unconstrained optimization technique. The softwares used in this work include, MATLAB for the calculation of femur strength, length and diameter, CATIA V5R20 for the designing and modeling of human femur bone and human femur intramedullary rod and ANSYS 16.0 for the analysis of the stresses acting on the designed models. Results of this work gives the optimized length and optimized diameter of the human femur intramedullary rod required for the 31 female human individuals considered with different heights. The designed model helps in the easy insertion of the intramedullary rod during surgery due to its simple design. These dimensions can be useful in further study and minimization of the femur implant failures.