The present study is directed to summarize several studies carried out in the recent past on stone decay processes taking place in the lagoon environment of Venice. The behaviour of the main types of stones used in Venetian buildings has been considered. Istrian stone, Verona red stone and Carrara marble were studied. The knowledge of the porosity and of the pore size distribution can contribute to clarify the physical transformation of decayed materials. The research determined the morphology of stone decay processes for the different types of stone. As far as the morphology of deterioration is concerned, there are two main types of decay which depend on the intrinsic properties of the stone: chemical-mineralogical composition and texture-structure.