Porosimetry of matured cementitious materials is of hiigh interest, because durability is governed by the capillary pore network structure. Experimental approaches are time-consuming, laborious and thus expensive. Fast developments in computer technology make it nowadays possible quite realistically producing cementitious materials in virtual reality by DEM. This renders possible studying the materials in a reliable and economic way This involves the production of fresh material, hydration to get the matured material, delineation ofthe capillary pore network system, and assessment of pore characteristics. Finally a model can be constructed correlating the obtained pore characteristics with global hydraulic properties of the cementitious material. The paper concentrates on the porosimetry methodology, however is illustrated by some results obtained this way on (blended) cement paste.