Wild fish is the important food resource and species are used as guides of nature water quality. Special attention should be paid to determination of heavy metal burden of waters in the Ob river basin as the anthropogenic load to aquatic ecosystems of this region increased and signs of the natural matter circulation disruption were observed. Perches (Perca fluviatilis) were sampled in the Ob river basin, specifically in middle reaches of Ob river and lower reaches of Tom river, in the summer of 2015. Sample processing and separation of soft muscular and osseous tissues were made according to standard practice. Contents of Cu, Fe, Mn, Zn were determined by the method of atomic-emission spectrometry with inductively coupled plasma (ICP AES) using Thermo Scientific’s «iCAP 6300 Duo». The content of Hg was measured by the analyzer RA-915 according to the atomic adsorption method. Average values of elements contents in the muscular tissue and concentration variation ranges were relatively Fe – 14.00 (6.44 -24.20), Zn – 7.31 (6.10 – 10.20), Mn - 1.16 (0.38 – 3.61), Сu – 0.43 (0.26-0.70) mg per a kilogram of wet weight. The mercury concentrations in investigational samples were within 0.008-0.119 mg/kg in the muscular tissue and were in the range 0.036-0.556 mg/kg in osseous tissue. The mercury concentrations in the osseous tissue were higher compared with values of the muscular tissue of all tested samples. In the region of intensive oil production in lower reaches of Ob river the mercury concentration in the osseous tissue was 0.556 mg/kg. Differences in characteristics of heavy metals and mercury storing were connected with particular habitat conditions. The ranking of metal concentrations found out in a perch Fe > Zn > Mn >Cu was representative for waters uncontaminated or slightly polluted by metals. Elevated Fe concentrations were found in samples picked up in river stretches contiguous to swamp lands and the Bakchar iron-ore deposit. Noticeable concentrations of Fe, Mn, Zn were related to areas of sideritic ore occurrence. Metals content in the muscular tissue of tested fish samples did not exceed the acceptable residual concentrations carried in Russia for fresh fish provision. The elevated Hg concentrations in some samples of lower reaches of Ob compared to maximum acceptable values may be explained by the anthropogenic way of intake of Hg with industrial out-emissions of oil production enterprises north of West Siberia.