The content of total mercury in organs and tissues (brain, muscles, kidneys, and liver) has been studied in common shrew and in common vole, living in different geomorphological regions of the Vologda Oblast. Mercury content is statistically significantly higher (2–5 times) in common shrew than in common vole. In common shrew, average mercury content (μg/g dry weight) decreases in the series: kidneys (0.158 ± 0.016) > liver (0.086 ± 0.01) > muscles (0.084 ± 0.011) > brain (0.059 ± 0.006); in common vole, kidneys (0.026 ± 0.003) > brain (0.024 ±0.004) > muscles (0.016 ±0.003) > liver (0.013 ± 0.002). Mercury content in organs of common shrew and of common vole, caught in the western geomorphological region with high swampiness and a large number of lakes, is statistically significantly higher (2–3 times) comparing to those captured in the eastern geomorphological region with a developed river network.