The effect of cyclic changes of temperature and the addition of organic matter on pore properties of model urban soil was investigated. Mixtures composed from a loessial soil with 10�50% w/w of rubble and 6% w/w of peat were studied. The mixtures were moistend to 25% of their field water capacity and subjected to cyclic changes of temperature. Before and after the cycles granulometric composition, organic matter content and mercury intrusion porosimetry studies were performed. Samples of the model urban soil before freezing-thawing cycles had lower values of the structural parameters than after cyclic changing of temperature. Those hanging concerned first of all the total cumu- lative volume and pore size distributions. The observed changes depended on the properties of added building materials, which changed to a greater extent under the cycles' change of temperature than the soils themselves.