The investigation of the soil enzymatic activity was carried out on the military airport of Dęblin in the areas of the point sources of contamination, and where a surface dispersion of the contaminants, caused by the aircraft engines, takes place. It was proved there is a reversed line relationship between the activity of the analysed enzymes and the contents of the oil-derived products in the soil. The effect of the interaction of the soil-derived contaminants on the enzyme activity depended both on the environmental conditions (soil pH, contents of the biogenic elements like N and P, contents o f heavy metals, soil sorption properties), and on the individual properties of a given enzyme.