Underground mining of chrome ores is characterized by constant exposure to chemical factors on production workers, which leads to the occurrence of pathological changes on the part of critical organs and systems. The aim of the study is to assess changes in the content of biochemical parameters and protein fractions in the blood serum of workers employed at an enterprise for underground mining of chrome ores. The content of chromium in the air of the working area and the blood of workers was assessed, a number of biochemical parameters were investigated by unified biochemical methods (IgE specific to chromium, ALAT, γ-HT, creatinine, β2-microglobulin in blood serum, β2-microglobulin in urine, calculation of the glomerular filtration rate) and protein fractions in blood serum using electrophoresis of proteins in agarose gel, modeling of cause-and-effect relationships was carried out. The workers of the mine mining of chromium ores showed a significant increase in the level of chromium in the blood up to 1.3 times, an increase in the level of IgE specific to chromium up to 1.6 times, the activity of ALAT and γ-HT in the blood serum up to 1.3 times, the level of β2-microglobulins in blood serum and urine up to 1.6 times, serum creatinine level, decrease in glomerular filtration rate, increase in serum β-globulin and γ-globulin level relative to similar indicators among employees of the enterprise employed outside the influence of a chemical factor. The constant presence of chromium compounds in the air of the working area leads to an increased concentration of chromium in the blood of workers. An increase in the activity of ALAT and γ-HT in the blood serum, the level of β2-microglobulins in the blood serum and urine, the level of creatinine and IgE specific to chromium in the blood serum, and a decrease in the glomerular filtration rate were found. Changes in protein fractions in blood serum (increase in the level of β-globulins and γ-globulins) were revealed in workers at the mine mining of chromium ores. Ethics. When conducting the study, the authors were guided by the ethical principles of medical research with human participation as a subject, set out in the Declaration of Helsinki by the World Medical Association of the last revision and received informed voluntary consent from each employee to participate in the survey.