Two methods of punch deformation of flat polymeric materials have been studied and compared between themselves. The areas of the method application for the determination of fabric mechanical and exploitation stability and also the suitability of methods for the evaluation of effectiveness of technological treatment with liquid chemical softeners have been analyzed. The geometrical and mechanical behavior of flat polymeric materials (woven and knitted fabrics) during pulling of a disc-shaped specimen through a central hole of KTU-Griff-Tester has been analyzed on the basis of pulling parameters.