Aeration related properties of individual soil layers of three Slovakian soil profiles (Calcaro-haplic Phaeozem, Fluvi-calcaric Phaeozem and Calcaro-gleyic Phaeozem) were characterised with the use of undisturbed soil samples preincubated on water tension plates at 0, 63, 159 and 500 hPa at room temperature. The experiment included measurements of air-filled porosity (Eg), relative gas diffusion coefficient (D/Do), air permeability (k), oxygen diffusion rate (ODR), redox potential (Eh), content of Fe+2 as well as soil dehydrogenase and catalase activities. The soils under investigation showed high resistance to reduction processes. Despite O2 depletion following 2-days water saturation (expressed by the low values of ODR, k, D/Do and Eg), the redox potential was still maintained on a high level and concentration of the reduced iron was relatively low. A close relationship between aeration parameters was found.