We study experimentally the scale effect for the strength of elastomer fibers under tension. We test fibers of an un-sewn caoutchouc of block-copolymer of dimethyl-styrene with poly-butadiene of the diameter in the range 2–118 microns. We make the conclusion that strength increases with the decrease of the initial diameter of fibers. We study how the preliminary fixed orientation of fibers influence on the strength of materials. We discuss the reasons for wide dispersion of values of tensile deformation of thin fibers.