The purpose of this study was to use magnesium (50 and 100 mg Mg kg-1) to neutralise possible nega-tive effects of soil contamination with cadmium (10, 20, 30 and 40 mg Cd kg-1) on the enzymatic activity of soil. Soil contamination with cadmium depressed the activity of dehydrogenases, urease, alkaline phospha-tase and, to a smaller extent, acid phosphatase. In addition, cadmium pollution narrowed down the potential biochemical fertility index of soil under yellow lupine. Application of magnesium to soil alleviated the unfavourable impact of cadmium on dehydrogenases during the shoot elongation phase. Such positive influence of magnesium on urease was observed both during the shoot elongation phase and at harvest, and in the case of alkaline and acid phosphatases it occurred only at harvest.