We explore the influence of nuclear accident at the Mayak Production Association to the genetic structure of pygmy wood mice populations. 100 mice were trapped in the contaminated areas. From 28 to 154 individuals were trapped at six control site. Eighteen allozyme loci were used, three of them were polymorphic. We hadn’t found a difference between EURT and uncontaminated population in the main parameters (allozyme diversity, alleles and genotype frequencies). So we concluded that the features of allozyme structures of Apodemus uralensis population from the EURT zone are absent.