This study concerns experimental results of a chemical-physical and mineralogical characterisation of some mortars, sampled by different masonries brought to light during excavations of the site of Monte Sannace. The aim of the research is to provide, through the characterisation of the mortar samples and the relative raw materials, useful information in order to define the stages of construction and the workers' technological knowledge during different historical periods. DTA/TG/DTG thermoanalytical investigations and X-ray diffractometry analyses can allow to define the nature of both the binder and aggregate materials. As regards a specific mortar with hydraulic behaviour such a study has allowed to recognise also the residual reactivity towards lime of the 'pozzolanic' sand, rich in volcanic ashes, used as aggregate in the original mortar. The thermoanalytical and X-ray diffractometric results together with the granulometric and chemical determinations allow to et information about the preparation techniques of binding materials of old masonries. (C) 2004 Elsevier B.V. All rights reserved.