This study develops an analytical expression to describe the cyclic stress-strain curve obtained from a series of fully-reversed fatigue tests. A set of stress-strain relationships is proposed to simulate the tensile branch of the stable hysteresis loop. The complete shape of the stable hysteresis loop is then constructed and the associated theoretical plastic work calculated by integrating the area within the enclosed curve. The theoretical plastic work is employed to predict the fatigue lives of the investigated materials on the basis of their respective stable plastic work per cyclelife curves. In this paper, the current mathematical derivations are based upon the endochronic theory of plasticity. The accuracy of the proposed set of stress-strain relationships is verified by conducting fully-reversed constant strain amplitude fatigue tests on AISI 316 and AISI 304 stainless steels. The experimental and simulation results are found to be in good agreement, hence confirming the accuracy of the proposed analytical stress-strain relationships. Again, comparing the obverted and predicted fatigue lives, a good agreement is found between the two sets of results. © 2005, Taylor & Francis Group, LLC.