The study was performed on a pot experiment in which a grey-brown podzolic soil was amended with two different doses of dairy sewage sludge (30 and 75 t ha-1) – 1 and 2.5% of DSS. During periode of incubation in different terms of analyses (7, 14, 30, 60, 90 and 120 days after the incorporation of dairy sewage sludge) the following analyses were done: so-called total number of bacteria, so-called total number of filamentous fungi, number of cellulolytic bacteria, respiration activity and dehydrogenase activity. Dairy sewage sludge applied to the soil caused stimulation of the total number of bacteria, fungi and cellulolytic bacteria and respiration activity and inhibition of dehydrogenase activity in a grey-brown podzolic soil.