Persistent organic pollutants present in the soil are a major source of contamination for both the environment and population. Due to the high toxicity that it represents, a series of studies to establish the mechanisms for destruction of POPs and reduction of their risks were undertaken. According to current scientific data, iron oxide nanoparticles (NPs) possess the ability to transform or destroy POPs in the soil. Strains of bacteria Bacillus cereus var. fluorescens CNMN-BB-07 and Bacillus subtilis CNMN-BB-117 from the National Collection of Nonpathogenic Microorganisms of the Institute of Microbiology and Biotechnology of the ASM were used as object of our research. These strains were grown on agar nutrient medium, with the trifluralin as a POP and iron oxide NPs (Fe3O4). Cultivation was carried out in Petri dishes in the thermostat at a temperature of 35±2°C. Iron oxide NPs were synthesized by Tatiana Gutul, scientific researcher of the Nanotechnologies Laboratory, Institute of Electronic Engineering and Nanotechnologies, ASM. The aim of the research was to determine the ability of iron oxide NPs to reduce the toxicity of POPs in the presence of bacteria isolated from soil. The results obtained in this study allowed us to affirm that the presence of trifluralin in concentration 200 mg/L of in the cultivation medium decrease the viability of Bacillus cereus var. fluorescens CNMN-BB-07 and Bacillus subtilis CNMN-BB-117 with 3.3–4.1% compared to the control sample (Figure 1). The administration of POPs in concentration of 200 mg/L and iron oxide NPs (Fe3O4) in concentrations of 25 and 50 mg/L led to the trifluralin toxicity reduction, thus the viability of the studied cultures tend to an insignificant increase. It was also established that for the strain Bacillus subtilis CNMN-BB-117, the presence in the cultivation medium of iron oxide NPs (100 mg/L) and trifluralin (200 mg/L) caused the decrease of viability with 6.7% compared to control sample and with 3.4% compared to trifluralin sample. Therefore, we can conclude that the concentration of 200 mg/L of trifluralin inhibits insignificantly the viability of bacterial strains (up to 4.0%), and the presence of iron oxide NPs at concentrations of 25 and 50 mg/L have a tendency to increase slightly the viability. Iron oxide NPs in concentration 100 mg/L decreases the viability with 6.7% compared to control and 3.4% compared to trifluralin sample.