One of the promising methods of biogas upgrading is biological methanation (biomethanation). During biomethanation process hydrogenotrophic microorganisms use carbon dioxide from biogas and added hydrogen to generate biomethane. Application of biotrickling filter reactors is one of the prospective biotechnologies for methanation where hydrogenotrophic methanogens are immobilized over a material that is used in reactor. Packing materials for biomethanation are critical in terms of hydrogenotrophic methanogens immobilization on the surface of packing material. It acts as support for biofilm growth. Therefore, characteristics of filter material are important parameters that influence the growth of microorganisms and methane production. Factors, such as optimal specific surface area and porosity are important to sustain growth and activity of microorganisms. Optimal particle size and capability to mechanically resist compaction ensures avoiding high pressure drop. Optimal particle size also ensures uniform gas flow as gases distribute through the packing material. This review paper summarizes and compare the characteristics of different packing materials important for biomethanation through ex-situ biotrickling filter reactor systems.