Petrographic analysis and chemical, physical and morphological, climatological, and biological testing was performed on the marbles of the Pavia Certosa church facade, entailing the collaboration of specialists in the related disciplines. The degredation is of a chemical nature on the Candoglia marble (calcite dissolution by acid waters); of chemical-physical nature on the Carrara marble (calcite dissolution by acid waters; gypsum crusts by sulfation, pulverization by thermal excursions). The mechanisms of degradation are entirely due to the severity of environment, both past and present.