Carbon nanotubes (CNTs) do have the potential to improve the interlaminar shear strength (ILSS) of composites if they can be successfully integrated into the matrix as it infuses into the fiber preform. The infusion under capillary action of Multi-Walled Carbon Nanotubes (MWNT)/Epoxy suspension with tubes of length 0.3 approximately 1 microm in glass fiber bundles containing pores of the order of 5 nm approximately100 microm was investigated. The influence of parameters such as suspension concentration, viscosity, porous media architecture, surface tension and contact angle were explored. It was found that filtering of the suspension is a major challenge for uniform infusion for concentrations beyond 0.5% MWNT by weight. This is even truer for fiber bundles that are compacted. Hence for successful manufacturing, new infusion techniques that rely on fabrics of high permeability will have to be developed to fabricate such nanocomposites.