The development of Human Genome Project (HGP) makes it possible and more important to reveal the variations or polymorphisms precisely between different individuals and populations. Due to the characters of their high polymorphism and value in disease-linkage analysis as well as pharmacogenomnics, genetic markers on X chromosome have attracted much more attention of current medical and forensic scientists. This report summarized the proceeding of research on X chromosome genetic markers in the clinical and forensic context.