Realistic modelling of porous media is difficult. Different models are proposed depending on the property to be modelled, for example, porosity, permeability, electrical resistivity. Anisotropy is seldom considered. This paper examines the pore structure obtained for packs of spheres, with emphasis on the anisotropy. The structures can be reduced to an equivalent network which demonstrates that anisotropy of the pore structure is present even for homogeneous packs of spheres. The influence of anisotropy on the various porous media properties such as permeability, electrical resistivity and convective dispersion is highlighted.