An increase in the number of drugs, including antibiotic substances entering the environment, necessitates studies of their impact on the functioning of ecosystems. In the global cycle of substances, the nitrogen cycle is one of the main processes. An important role is played by the nitrification process. For the first time, the effect of antibiotics of different groups: oxytetracycline, tylosin, benzylpenicillin on the nitrifying activity of sod-podzolic soil under their individual and combined exposure by laboratory modeling, was studied. As a result of studies, it was found that with individual influence, these drugs did not have a significant effect. However, a mixture of benzylpenicillin and tylosin stimulated nitrifying activity at 50 mg/kg of soil and inhibited at 300–700 mg/kg. Under the influence of a mixture of three antibiotics in the range of 50– 300 mg/kg of soil, the nitrification process intensified and was suppressed at 400–700 mg/kg.