Compaction and permeability behaviour are important influences on the processing of composites for a range of manufacturing techniques including liquid composite moulding (LCM) and compression moulding. This paper describes an experimental study of the factors influencing these characteristics for two glass fibre reinforcement media used in LCM: continuous strand mat and an aligned fabric produced using warp knitting technology. The compaction relationships for the materials are presented as functions of process variables such as pressure, temperature, and forming rate. In plane permeability relationships measured using rectilinear and radial flow tests are presented for different fibre orientations and packing fractions. The results are discussed with reference to processing by resin transfer and structural reaction injection moulding.MST/3248