The aim of the study was to determine how soil contamination with petrol and diesel oil affected content of some macroelements in spring oilseed rape (Brassica napus var. oleifera) and oat (Avena sativa L.) and to determine whether application of compost, bentonite or calcium oxide could reduce the impact of petroleum-derived products on the properties of the plants. The soil formed from sandy loam was polluted with the following amounts of petrol and diesel oil: 2.5, 5.0 and 10 cm3⋅kg-1 of soil. The results of the tests showed that contamination of soil with diesel oil at the amount between 2.5 and 10 cm3⋅kg-1 of soil disturbed the plants’ chemical composition. Irrespective of the application of compost, bentonite or calcium oxide, the highest doses of petrol and especially diesel oil decreased the content of most macroelements in spring oilseed rape and, to a smaller degree, in oat. Enrichment of soil with compost, bentonite or calcium oxide modified the content of macroelements in plants, mainly that of sodium under the effect of bentonite. Significant correlations, mainly between the content of some macroelements in spring oilseed rape and oats versus plant yield and content of other elements in plants, as well as some properties of soil were observed.