With their properties, upholstery covering materials significantly influence the quality of upholstered products. These materials form the surface layer of upholstered furniture; any damage to this material is immediately visible to the user. We consider the stitches connecting the covering fabrics to be one of the critical points of the upholstered surface, therefore they must have the required strength. Faux leather is one of the most used upholstery materials. The main aim of the paper is to determine the effect of upholstery faux leather, stitch length, point needle, and needle size on the strength of the stitches and the seam efficiency. The results of the experiment proved the suitability of using a sewing needle LR for joining covering materials such as faux leathers. The highest force to seam a rupture in the joints was achieved in the direction of the warp yarns of the underlying layer of PU (Polyurethane) faux leather with a stitch length of 4 mm and needle type LR/90. The highest seam efficiency was achieved with seams in the direction of the weft yarns of the PVC (Polyvinyl chloride) faux leather underlying layer with a stitch length of 4 mm and needle type LR/90. If the underlying layer of faux leather is a fabric with canvas binding, a higher seam efficiency of joints is assumed.