Background: in the postgenome era, G-protein-coupled receptor families have been recognized as significant drug targets in medicinal chemistry. A specific chemokine receptor, CXCR4, has multiple critical functions in normal physiologies including embryonic development of the cardiovascular, hemopoietic and central nervous systems, and underlies problematic pathologies such as HIV infection, cancer metastasis, leukemia progression and rheumatoid arthritis. Methods and results: A tetradecamer pepticle, T140, derived from the horseshoe crab, and its biologically stable derivative, 4F-benzoyl-TN14003, were found to be powerful CXCR4 antagonists that block HIV entry to cells. These peptides have also shown remarkable inhibitory activity against cancer metastasis and progression in a variety of cancers. Slow release administration of 4F-benzoyl-TN14003, for example, was found to significantly reduce pulmonary metastasis of breast cancer cells in severe combined immunodeficient mice. This peptide also shows inhibitory effects against melanoma metastasis and Epstein-Barr virus-associated lymphoproliferation in mice, suppresses the delayed-type hypersensitivity response induced by sheep red blood cells and reduced collagen-incluced arthritis in both mouse models of arthritis. Conclusion: T140 analogues have the potential to become promising agents for chemotherapy of AIDS, cancer and rheumatoid arthritis. This review summarizes the development of low molecular weight CXCR4 antagonists based on pharmacophore identification in T140 analogues and also provides an opinion on the future of the development of CXCR4 antagonists.