In the chapter we consider some mathematical models of hydriding of metal powders. Our aim is to choose the most significant factors in order to construct adequate but rather simple models. We describe the process of non-metal hydride formation for a single particle and focus on the case of hydriding with formation of a hydride skin on the surface of a particle. Mathematical models are constructed for this case. We present the results of fitting the series of experimental curves in order to estimate kinetic parameters and study the influence of the powder particles' shape. It is shown that different shapes provide similar results and thus the shape is insignificant. Then we add some factors, previously not taken into account: changing pressure, heat releasing effects accompanied by changing temperature, different heat capacities of metal and hydride phases and hydrogen. Significant release of heat during hydriding is an important problem when constructing hydride hydrogen storage systems. The model contains a non-classical boundary-value problem; we describe how to transform it so that it could be easily solved numerically. Finally we describe an approach to modeling a real powder: in the case of quick sorption we have the heat-controlling hydriding with concentration redistribution between the particles. We construct the discrete 1-D, 2-D, and 3-D models that are convenient for parallel calculating.