Pressure casting dies are subjected to a large number of thermal as well as mechanical load cycles, which may lead to a characteristic thermally induced crack network on the die surface. The cyclic thermo-mechanical behavior of the hot work tool steel grade 1.2343 (X38CrMoV5-1), representing a typical die material, is investigated both experimentally and numerically. An elastic-viscoplastic material model is calibrated using isothermal compression-tension tests and validated by means of a special non-isothermal experimental device. The material law is finally used for the prediction of stresses and strains in a die. The finite element models of the pressure casting dies consider besides the elastic-viscoplastic material behavior non-linearities in the form of contact, latent heat and temperature-dependent thermo-physical material data of the melt as well as of the die. They are performed using ABAQUS/Standard and Zmat. Two types of models are provided: representative 2-dimensional models to investigate local phenomena and the sensitivity to parameter and geometry variations, and a global model of a section of a real die to give an overview of the loading situation and serve as the basis of a detailed submodel. The results show the formation of residual stresses as well as a map predicting the local loading hotspots. The simulation results are in a very good agreement with experimental data as well as real life observations on dies used for serial production.