Abstract <p>Bioaccumulation of heavy metals in the tissues (fur, muscles, liver, bones) of free-living striped field mouse (<i>Apodemus agrarius</i>) was studied in four parks in Moscow, located at different distances from the city center and in areas with varying degrees of anthropogenic impact. The content of eight heavy metals (Fe,&#xa0;Mn, Zn, Cr, Ni, Sr, Cu, Pb) and metalloid As was quantitatively analyzed by X-ray fluorescence analysis. It has been shown that the accumulation of heavy metals in the tissues and organs of mice living in the studied parks occurs in different ways. Most of them accumulate in fur, less in muscles, liver and bones (with the exception of Sr, which did not always have the highest concentration in fur, and Ni, with a maximum in muscles). Significantly higher concentrations of metals were found in samples from the Filevsky Park (significantly higher concentrations were noted for Mn, Fe, Cu, Zn, Cr, and Ni). The accumulation of Sr by fur was higher in Neskuchny Garden, and Pb—in Ostankino Park. Terletsky Park is the most distant from the city center, it is the least polluted in terms of bioaccumulation in fur, muscles and liver, despite the high score of “environmental disadvantage,” Thus, metal bioaccumulation occurs in different ways in the tissues and organs of free-living striped field mice, while the distance from the city center and the comprehensive environmental well-being score do not always affect this indicator. To assess the environmental situation in different parts of the city, it is necessary to develop a more complex analytical panel, taking into account the seasonal and spatial dynamics of the circulation of pollutants, their cumulative effects and different metabolic mechanisms.</p>