The development of industry, especially oil and chemical branches, resulted in the contamination of the natural environment by oil-derived compounds, including polycyclic aromatic hydrocarbons (PAHs). These compounds are highly toxic to the living organisms, most of them expressing carcinogenic properties. Microbiological degradation is one of the main methods of removing PAHs from the environment. Biodegradation reduces the costs of recultivation by considerable acceleration of the degradation of those compounds in the soil. Microscopic fungi play an important role in the process of PAHs detoxification and degradation. Our studies have shown that a number of strains involved in the steroids transformation are also capable of PAHs degradation. Due to the fact that both processes involve the participation of cytochrome P-450, these strains are convenient research models for explaining the dependence between steroid hydroxylases and enzymes responsible for PAHs degradation. The currently performed research is aimed at developing the possibilities of employing microorganisms used for the production of steroid drugs in the protection of the environment.