The clearing of Mediterranean maquis along with the creation of new pasture land has been an important factor of soil and land degradation in the Mediterranean region. The present research compared soil aggregates and their intraporosity in paired pasture/maquis plots in central E Sardinia (Italy), to study the impact of land use change on soil structure. Undisturbed surface horizons were sampled for thin-section analysis. Aggregate shape was compared and intraporosity was studied for representative aggregates at different depths. Furthermore, the interaction of root activity and grazing under pasture and maquis cover was discussed. The outcomes revealed a complex interplay of trampling and root activity effects. A decrease (-44%) in total voids (regular pores), along with higher aggregate regularity, was observed under pasture in the 0-2cm layer, and an increase (+261%) in 50-100 m planar (elongated) pores was determined in the 2-4cm layer, suggesting a possible surface compaction due to trampling and an increased subsurface fine root activity by the grassland vegetation.