For sustainable soil use soil quality is essential presumption. Soil quality does not depend only on the physical and chemical properties of soil but it is very closely linked with the biological properties of soil mostly on microbiological processes. Soil quality is a dynamic feature, and any significant indicators must be sensitive to small changes in key soil properties. During the years 1991-2002 soil samples were collected at four Cambisol localities (totally 184 samples) and five Luvisol localities (totally 230 samples). Chemical (soil organic carbon [Corg], total nitrogen [Nt], pH KCl), textural (content of sand, silt, clay particles) and biological characteristics (microbial biomass carbon [Cmb], K2SO4 extractable microbial carbon [Cex]), respiration, ammonification, nitrification) were studied. The higher level of Corg (1.20-1.76%) characterised Cambisols and resulted in quite high microbial biomass carbon content (396—625 ug/g dry soil, average 556, SD 167). For these soils high control respiration (0.45-0.80 mg C02/h/100 g dry soil) and potential nitrification with (NH4)2S04 (6.7-18.4 mg N-NO3/8 days/100 g dry soil) were typical. Studied Luvisols reached lower levels: Corg (0.97-1.22%), Cmb (398-503 eg/g dry soil, average 455, SD 98), control respiration (0.46-0.57 mg C02/h/100 g dry soil), potential nitrification with (NH2)4SO4 (3.2-9.9 mg N-NO3/8 days/100 g dry soil). Mentioned lower level of organic carbon and medium level of microbial biomass raised in higher ratio Cmb/Corg (average 4.0%).