The authors present a generalization of the classical Preisach model which handles coupled magnetic and mechanical hysteresis. Magnetostrictive materials are known to have hysteresis with respect to both magnetic field H and mechanical stress lambda . To test the validity of the model, experiments where the two components H and lambda have been verified in many different ways have been performed on Terfenol-D and compared to results computed from the model. Some of these results are presented. This stress-dependent model is found to have an accuracy comparable to that of the classical Preisach model. >