Permeability of fabric preforms and its changes due to various modes of the fabric distortion or deformation as well due to fabric layers shifting and compacting is one of the key factors controlling infiltration of the preforms with resin within the common polymer-matrix composite liquid-molding fabrication processes. While direct measurements of the fabric permeability generally yield the most reliable results, a large number of the fabric architectures used and numerous deformation and layers rearrangement modes necessitates the development and the use of computational models for the prediction of preform permeability. One such model, the so-called lubrication model, is adapted in the present work to study the effect of the mold walls, the compaction pressure, the fabric-tows shearing and the fabric layers shifting on permeability of the preforms based on orthogonal balanced plain-weave fabrics. The model predictions are compared with their respective experimental counterparts available in the literature and a reasonably good agreement is found between the corresponding sets of results. (C) 2004 Elsevier B.V. All rights reserved.