The process of HIV entry begins with the binding of the viral envelope glycoprotein gp120 to both the CD4 receptor and one of the CXCR4 or CCR5 chemokine co-receptors. There is currently considerable interest in developing novel ligands that can bind to these co-receptors and hence block virus-cell fusion. This article reviews the use of different in silico structure-based and ligand-based virtual screening (VS) tools for the discovery of potential HIV entry inhibitors for the CXCR4 receptor. More specifically, it discusses homology modelling, de novo design, docking, QSAR analyses, pharmacophore modelling, and similarity searches. Results from retrospective VS of a library of known CXCR4 inhibitors taken from the literature and from prospective VS of a combinatorial virtual library are reviewed. The structures of active compounds found by these approaches, as well as CXCR4 inhibitors currently in development, are also discussed. Drug Dev Res 72: 95–111, 2011. © 2010 Wiley-Liss, Inc.