Oil and petroleum products are a signifi cant source of environmental pollution, leading to the accumulation of hydrocarbons in the soil profi le. They contaminate groundwater, disrupt natural soil biochemical processes, interact with mineral compounds – thereby reducing their bioavailability to plants – and cause the poisoning and death of living organisms. The study of hydrocarbon-oxidizing microorganisms is of considerable practical importance due to their ability to degrade hydrocarbons. Analyzing the adaptation mechanisms and stress resistance of degrading bacteria enables the prediction of bioremediation effi ciency under various ecological scenarios. This work investigates the infl uence of temperature, NaCl concentration, and pH on the growth and biofi lm formation intensity of hydrocarbon-oxidizing bacteria isolated from soils with high levels of oil contamination. The substrate specifi city of the oil-degrading bacteria was also studied. The strains Paenibacillus polymyxa S31 and Citrobacter freundii K29 were the most tolerant to abiotic environmental factors. P. polymyxa S31 exhibited the broadest substrate specifi city, as it was capable of degrading all tested substrates. Maximum biofi lm production by all studied strains was observed at 28°C. For strains Bacillus circulans D18, Bacillus licheniformis M88, Bacillus muralis V16, Bacillus pumilus L27, and P. glucanolyticus F15, the maximum production occurred in an alkaline environment (at pH 9), while for strains C. freundii K29 and P. polymyxa S31, it was in a neutral environment (at pH 7).