Clinical signs of the presence of immune dysfunction/insufficiency, identified by questioning workers at the landfill for the storage and destruction of industrial toxic waste, were the basis for performing a screening study of immune status. This included a clinical blood test with determination of the leukocyte formula, assessment of the phenotypic status of lymphocytes for the main subpopulations, determination of the concentration in serum immunoglobulins of various classes, assessment of the migration activity of leukocytes, assessment of the microbicidal capacity of neutrophils and their ability to phagocytosis. When the examined employees were found to have more than 20% changes in the normative range of immune status parameters and the presence of combined disorders in different parts of immunoreactivity, in particular combined disorders in the cellular part of the immune system, it was the basis for conducting an in-depth stage of immunoepidemiological examination. This included determination of functional activity cellular elements of the adaptive component of immunity, assessment of the severity of autosensitization, assessment of the severity and specificity of atopic hypersensitization, assessment of cytokine status in normal conditions and in response to mitogen. When assessing the phenotypic status of immunoreactivity cells, it turned out that the absolute number of T lymphocytes (CD3+ phenotype), helper T lymphocytes (CD3+CD4+ phenotype) and killer T lymphocytes (CD3+CD8+ phenotype) was significantly reduced in the peripheral blood of test site employees (p ≤ 0.05, compared with similar indicators in the control group). On the contrary, the content of NK cells (CD3-CD56+ phenotype) tended to increase (both the absolute number and the proportion among other lymphocyte populations). Dysfunction of the cellular component of humoral immunoreactivity (a significant decrease in the absolute number of lymphocytes with the CD3-CD20+ phenotype [B lymphocytes] in the peripheral blood), as well as a significant increase in the concentration of serum IgA-class immunoglobulin and pronounced disimmunoglobulinemia in the serum of the examined individuals (compared to individuals in the control group ) indicated a predominantly inhalation method of exposure to immunotoxic industrial toxicants from the landfill on the immune system. Pathogenetically targeted immune-oriented therapy for the personnel of the test site was carried out with drugs that have thymomimetic activity (cytovir-3, thymogen) and are a means of replacement immunocorrection with a cytokine drug (genetically engineered recombinant yeast IL-2 [roncoleukin]). The established effectiveness of the immunotherapy, in particular the reduction in the incidence rate of various nosological forms of immune-related pathology among the site employees who received immunotherapy and the presence of an immunocorrective effect in the immunoactive drugs used for therapy, indicate the advisability of carrying out preventive medical measures in persons professionally exposed to xenobiotic influences as a component of improving medical provision.