Pneumoconiosis (Pc) are interstitial pulmonary diseases of professional genesis, caused by long-term inhalation of high dust concentrations. Pc affects from 26.6 to 53 percent of professional workers associated with dust contamination. The peculiarity of the course of Pc is in its incurability and irreversibility. Pc was modeled in 72 albino rats by endotracheal injection of a suspension of coal according to its own modification of the technique O.Yu. Nikolenko. The activity of lipid peroxidation and enzymes of the antioxidant protection system was related to the sickness period. The development of experimental Pc led to the increasing level of malonic dialdehyde in 1.68–3.05 times in the blood, and also increase in the level of diene conjugates, and triene conjugates 2.43–5.63 times, depending on the duration of the disease. 1.77–4.42 times decrease in catalase, superoxide dismutase, and glutathione peroxidase activity, alongside with 1.56–2.02 times increase in glutathione reductase activity, depending on the disease phase, occurred. The content of reduced glutathione decreased in proportion to the duration of the disease. Initiation of lipid peroxidation and suppressed activity of antioxidant protection system enzymes may be among the pathogenic mechanisms of experimental Pc development.