Enzyme activity is a sensitive indicator of fertility, metabolic processes and circulation of matter as well as soil environment contamination. Dehydrogenases (EC 1.1.1.1) are the kind of enzymes belonging to oxidoreductases class, which catalyzes oxidation and reduction reaction. Their activity give information on soil microflora oxidative activity and intensive matabolism of soil microorganisms. Heavy metals, PAH’s or pesticides decrease the soil dehydrogenase activity. Glyphosate is the most common herbicide used worldwide and as other pesticides is toxic for living organisms. The aim of the study was to determi- nate dehydrogenase activity (DHA) in the soils enriched with glyphosate (1 µg and 10 µg g-1 of pesticide doses) during time (42 days), under laboratory conditions at temperature 20°C. The de- crease of DHA activity was observed that depended on the pesticide dose.