Empirical modeling of dynamic hysteretic behavior of a wire-cable vibration isolator is described. Experimental tests showed that, under steady periodic excitation, the dynamic hysteresis loops of the isolator depend on the vibration level, but are almost independent of vibration frequency. On these grounds, a simple mathematical model representing restoring force versus displacement, with amplitude-dependent parameters, is presented. This model is convenient for steady-state dynamic response analysis of nonlinear hysteretic systems. For identification of hysteresis loops of the isolator under steady harmonic motion, an alternative but direct procedure, based on the FFT and Chebyshev polynomial approach, is also proposed.