State of deterioration of materials in two historic monuments of the University of Pavia: the Main Building of the University (Palazzo Centrale dell'Ateneo) and the group of buildings that formerly constituted the monastery of San Felice. The main cause of the deterioration of carbonate rocks and calcitic cemented sandstone is the gradual transformation of the carbonates into gypsum, which because of associated expansion causes the decohesion and separation of the areas damaged by the action of the sulfureous gases present in the urban atmosphere. The following types of action are proposed: straightforward cleaning of the granite elements, protection with epoxy resins, substitution of other elements.