Localization of genes GALA, G6PD, HPRT and PGK on X-chromosome of Microtus subarvalis has been proved. Using the radiation hybrid mapping technique of Goss and Harris, the order of these genes for two species M. subarvalis and M. Kirgisorum was established. Statistical methods (program package RHMAP) result in the only gene order PKG--HPRT--G6PD--GALA for M. subarvalis. The same order was found to be the most probable for M. kirgisorum. Relative distances between these genes in two species appeared to be practically equal. A conservatism of a linear order of the X-linked genes in various mammalian taxons is discussed.