The influence of compaction water content on the structure has been well known for clayey soils, but has never been studied for granular materials. In this paper the effect of compaction moisture on the structure of a non-plastic till is investigated by means of scanning electron microscopy, water retention curve, permeability and mercury intrusion porosimetry tests. The results show that the structure of pulverulized materials, in some degrees similarly to cohesive materials, is affected by the compaction condition. When compacted on the dry side of the optimum water content, the porous system is characterized by a relatively uniform medium pores, while in case of compaction on the wet side, due to formation of coarse aggregates, pores size is very diversified. The few large pores are surrounded by numerous small pores, and the hydraulic behavior of the porous system of the soil is dominated by the small pores.