agging is one of the common permanent deformations of woven and knitted fabrics – especially garment fabrics. The places it is seen during wear are elbows, knees, pockets, hips, and heels. It has been assumed that when a prolonged compression force is exerted on a garment during wear, the three-dimensional deformation may involve complex inelastic behavior in the garment, including viscoelastic behavior of the fibers and plastic behavior due to frictional movements between fibers and between yarns in the fabric. Bagging force induces internal stresses at multi directions, including tension, shearing, bending where pressure and friction are external forces. Because the appearance of the garment is distorted and because this appearance is important from the aesthetic point of view in the daily use of the garment, such a subject involves a quality factor and must be studied. This research investigates the effect of fiber, yarn and fabric variables on the bagging behavior of single jersey weft knitted fabrics interpreted in terms of bagging fatigue percentage. In order to estimate the optimum process conditions and to examine the individual effects of each controllable factor on a particular response, Taguchi’s experimental design was used. A fabric’s permanent deformation behavior depends on the fiber properties of the material, as well as yarn and fabric parameters. Thus, the controllable factors considered in this research were blending ratio, yarn twist and count, knit structure and knit density. According to the levels of controllable factors, L27 array was selected. Bagging fatigue percentage of the knitted fabrics was considered as the response. The findings show that fabric structure has the largest effect on the fabric bagging. Factor yarn twist is second and is followed by fabric density, blend ratio and yarn count. The optimum conditions to achieve the least bagging fatigue percentage were determined. In this research, the plain structure, highest density, 75/25polyster-cotton yarn, the highest twist and the highest level of count were identified as optimum condition. According to experimental observations, bagging was also simulated using finite element method (FEM). The study of the mechanical behavior of the plain knitted fabric was based on the modeling of the fabric mezzo structure. The geometrical complexity of the knitted fabrics unit cell, the coexistence of elongation and bending of the yarns in the deformation process, the yarn profile flattening and the interaction phenomena between yarns in the contact areas have a significant influence on the mechanical behavior of the knitted fabrics. For modeling of the yarn, two kinds of elements; wire and solid and two kinds of elastic properties; isotropic and transverse isotropic properties were investigated. The findings showed that solid element and transverse isotropic elastic property can explain better the mechanical behavior of the yarn in knit structure. Finite element model presented in this study showed good agreement with the experimental results. Bagging resistance of the fabric was used as an important parameter to evaluate the present finite element results and experimental observations.