A satisfactory description of the tensile stress-strain dependences (SSDs) of lightly crosslinked single-phase networks is not obtained with use of the existing theories (Langevin, van der Waals, slip-link). A combination of the Langevin theory-based James-Guth equation with the phenomenological C-2 term of the Mooney-Rivlin equation (JGC2 equation) is shown to represent the SSDs of a number of networks (bimodal polysiloxane, pre-strained SBR) very well. Hysteresis-based deviations of some networks from the JGC2 equation in the high elongation region can be quantitatively taken into account as an increase in the finite extensibility parameter with extension ratio. The accuracy of the SSD description up to break is generally better than 3-4%.