This paper presents a numerical analysis of a high temperature extrusion process applied to bimaterial tubes made of two pre-bonded metallic materials with different plastic properties. The analysis has been carried out for different geometries and material combinations by using a FE code. An elasto-plastic behaviour with strain rate dependence has been assumed. A parameter related to the void growth rate at the bimaterial interface has been considered for fracture prediction during the extrusion operation.The influence of the different extrusion variables, namely the yield stress ratio, the location and relative thickness of the layers and the die angle, has been assessed. As a conclusion of the analysis, the yield stress ratio between the two materials turns out to be the most critical parameter of the process. Besides, the thickness fluctuations of the harder layer in the final product have been analysed for several material combinations. Those fluctuations can lead to an unacceptable geometrical heterogeneity under certain conditions. The results of the FE calculations are in reasonable agreement with the scarce data available from similar industrial operations.In short, the paper shows that use of FE calculations can be a pre-screening tool for the selection of material couples and extrusion conditions for the production of sound bimetallic tubes, before being engaged in very costly full-scaled trials.