Abstract: Yarn twist in spun yarns has the primary function of causing constraints and compressive stresses to be generated. It will be convenient, in the present study, to study the contact and inner pressure in a twisted yarn. The twist behavior of the multifilament was simulated using ABAQUS finite element package by modelling the yarns as 3D continuum elements. The study was conducted on the simulation of a 19 polypropylene filaments assembly with a circular cross section. Factors, such as dimensions and properties of filaments and interactions between filaments are included in the model. To simulate the torsion filament assembly was embedded from one side and twisted from the other. There after, we investigated the inner and contact pressure of all existing filaments inside the yarn. The results of this analysis showed highest level of contact pressure in the yarn surface that decreases while leading to the center as well as for the inner pressure and revealed the existence of migration in the twisted yarn. Moreover, the distribution of the inner pressure according to the radial position showed the presence of compressed and swollen zones in the twisted yarn.