i Degree: PH D Compression garments, due to their elastic structure, are generally used to provide a certain amount of pressure on the body parts and could be used for medical treatments, sportswear, clothing for pilots and astronauts, anti - shock clothing. The research findings have revealed that the fabr ic structural properties are not taken into account in designing and fabricating the compression garments. Therefore, the currently used pressure garments apply the pressure lower or greater than the required pressure. Many researches empirically investiga ted the relations between fabric structural parameters and applied pressure, but the performance of the compression garment in relation to yarn and fabric structures has not been yet simulated. In this paper, it is aimed to simulate the effect of yarn’s me chanical properties as well as fabric structure on mechanical performance of the compression garment. For this purpose, a precise geometrical model for fabric structure is needed by which the pressure applied to the body could be predicted. Accordingly, do uble jersey knitted fabrics containing two elastane weft yarns having different tensile properties, were produced on an electronic flat knitting machine and the fabric tensile properties were measured in course direction. Using equations governing the fabr ic structural unit - cell, a real geometric model was created in a finite element software environment. Considering the linear viscoelastic properties for elastane weft yarn, stress - strain curve was extracted. The results obtained from numerical simulation w ere compared with the experimental data in order to validate the proposed geometrical model. The findings demonstrated a good agreement between experimental and simulation results. For developing a three - dimensional biomechanical model for the leg system s upported by compression garment, images form computed tomography scanning methodology was used. Tensile properties of an elastane yarn as the basis for studying the compression garment’s mechanical behavior were experimentally measured and then simulated i n Abaqus software as a linear viscoelastic material. The results were then applied to multi - scale modeling technique in order to simulate mechanical behavior of the knitted fabric and the compression garment thereof. Combination of both experimental and th eoretical results was applied to simulate interactions between the leg and the compression garment. In order to achieve a comprehensive investigation, compression garments were prepared according to the leg’s dimensions of a healthy 26 – year old woman, 20 – y ear old man and a fatty 54 – year old woman. Using Kikuhime measuring device, experimental values of the applied pressure were measured in order to be compared with theoretical results. The results indicated that the pressure values simulated by finite eleme nt method for healthy 26 – year old woman, 20 – year old man and a fatty 54 – year old woman were predicted with the maximum error of 23.53%, 25% and 28.57% and total mean error of 9.6%, 12.98% and 16.84% compared to experimental results. The results showed a go od agreement between experimental and simulation results. Also, the results revealed that the type of the elastane weft yarns has significant effect on the pressure applied by compression garments produced thereof. The proposed model enables the specialist s to present compression garments based on the patient’s needs and physician prescription which generate the optimal treatment