Language: Persian : One of factors affecting quality of textiles is its appearance. During sewing and attaching fabric layers together, a deformation in appearance and junctions could happen. If these changes would be significant, a reduction in quality of the product will result. A main part of these changes is including fabric shrinkage and wrinkle creation due to the material types, adjusting parameters and conditions which is known as seam pucker phenomenon. Therefore, in this study, the effects of parameters such as fabric material, thread material, linear density of sewing thread, sewing thread tension, seam type, seam margin, stitch density, distance between the consecutive stitches and time relating to phenomenon of seam puckering were evaluated. For doing tests, two types of heavy cotton/polyester (50/50) fabric and light cotton fabric and four different sewing threads such as two polyester yarns with different linear densities, a nylon filament (nylon 6.6) and a nylon yarn (nylon 6) were used. Seam puckering of fabric layers was measured after 24h, 48 and 72h after sewing. Then, seam puckering values were compared to the results of measurement carried-out after sewing immediately. The obtained results showed that the specimen sewn with heavy fabric compared to light: fabric, because of more thickness and bending stiffness, has a lower seam puckering. Since polyester by less linear density and nylon6 yarns respectively have had the highest and lowest modulus of elasticity, then the highest and lowest of puckering was obtained for specimen sewn with less linear density and nylon6 yarns, respectively. Reduction of stitch density led to enhancing seam puckering. Decreasing the seam margin results in increasing the amount of puckering. Furthermore, by increasing the sewing thread tension or distance between the consecutive stitches parameter, resulted in an increase in seam wrinkle. In addition, the accuracy of experimental results were determined by using the results of analytical modeling. Moreover, according to the experimental results, the tension factor was the most effective parameter than other factors on seam puckering. The most important result of this study was that the seam wrinkling is a time-dependent phenomenon. Keywords: Appearance, Sewing, Seam, Stitch, Seam puckering, Linear density, Thread, Seam margin, Stitch density.