Recently, in connection with the increase in oil production and production of petroleum products, the process of alienation of land from agricultural use is gaining scale. Oil and petroleum products are recognized as priority environmental pollutants. Entering the soil, they primarily affect its biological properties. The chemical and physical properties of soils also deteriorate [1, p. 67]. As a result, soil fertility decreases, the soil becomes incapable of performing ecological functions. The aim of the work is: to study the influence of pollution by oil and oil products on the biological activity of ordinary chernozem [2, p. 31]. Scientific novelty of the work. A detailed study of the effect of oil and oil products on the biological activity and other properties of ordinary chernozems was carried out. A complex of microbiological, biochemical and other indicators of soil condition, a set of pollutants and the range of their content in the soil were also studied.