The fabrication of monolithic activated carbon fibre composites using isotropic pitch based carbon fibres, and phenolic resin as binder, is briefly described. The dimensional changes during drying, curing, baking and activation stages are presented and discussed. Data on other physical properties of the composites including their permeability and surface area are presented. With respect to gas separation, a technique developed to assess the potential of the composites to separate methane and carbon dioxide is described; the effects of some of the fabricating process variables on performance in CH4/CO2 separation is presented and discussed. In particular the effect of the extent of weight loss during activation on the final composite＇s properties is described.