This investigation was undertaken to examine in detail the effect of the strain ratio, Rε=εmin/εmax, on the cyclic behavior of Inconel 718 at 566°C. The results showed that the cyclic properties defined by the amplitude of the load-displacement hysteresis loops are independent of the mean stress. The complete cyclic curve, defined by the tips of the hysteresis loops, does depend on Rεat small strain ranges. At larger strain ranges where the plastic deformation allows the mean stress to relax, the effect disappears.