Diagnostic analysis, required to characterize materials and mechanical parameters of ancient masonry, needs a systematic collection and a careful reading of data results, as well as the cross-check of results of the different samples collected. This work assumes that diagnostic is part of the knowledge phase of existing buildings: knowledge level is fundamental to evaluate the state of conservation, as prescribed also in italian Technical Standards for Construction (2008). This paper describe some characteristics of a database system, M.A.I.D.A - Masonry Analysis Interpretation and Data Archive, performed to contain diagnostic analysis results of traditional materials and constituted by interactive analysis cards. Cards nomenclature and method follow UNI Normal rules for the construction materials: stones, bricks, mortars. Some tests on M.A.I.D.A system were carried out in a cooperation project between University of Parma and University of Rome ‘La Sapienza’. The project comprehends analysis of the Carolingian masonry and mortars from some buildings in Rome: SS. Quattro Coronati ecclesiastic complex, S. Francesca Romana Church and a Carolingian part of the Aurelian Walls in Rome. In order to enforce the data archives and to share the results M.A.I.D.A system will be put in a internet server.