The correlation analyses was used to assess the relationship between morphophysiological and biochemical parameters in liver of tundra voles from sites differing by level of natural radioactivity at Komi Repablic territory. It is revealed that the body mass males and females from the control and radioactive sites was a higher at the peak of the number of animals than that during the decline phase. In the phase of low abundance the relationship between the animal liver mass and body mass was growing stronger as the habitat radioactivity increases. The linear regression coefficient of this dependence was a 8 times higher in the radium impact sites, which indicates a decrease in the participation of lysoforms in the liver proliferative activity. The level of lipid peroxidation activity and the degree of unsaturated fatty acids in the peak and decline phases affected the severity of the relationship between the minor fractions of lipids metabolism in the liver and morphophysiological parameters of tundra voles. Taken together, the results of our study contribute to understanding of cell mechanisms of tundra vole adaptation to radioactive contamination, and dependence of morphophysiological and biochemical parameters on population heterogeneity and phase of animal abundance.