The void structure of porous materials used as catalyst supports affects several properties such as permeability to liquids, gas diffusion, organic molecules access, availability of oxidation/reduction active sites, and so forth. Mercury intrusion porosimetry has been widely used to investigate the accessible pore volume starting from about 3.6 nm up to more than 600 µm. The main limitation of mercury porosimetry is related to the measure of the access size to the porous network, to which the volume of mercury intruded, thus the pore volume, is associated. This generates an image of a simple bundle of cylindrical capillaries that might jeopardize further calculations that are related to pore size and pore volume, such as permeability and diffusion. An advanced technique of differential scanning porosimetry (DSP) has been applied to several catalysts supports to better describe the porous network distinguishing the access channels volume and size (pore throats) from the internal junction void volumes (pore cavities).