HERMES (HERitage Management E System) is a Digital Heritage Collection of Historic Buildings. It is the result of an 8 year research contucted by National Technical University of Atherns and Municipality of Hermoupolis. The main objective of this research is to evaluate the vulnerability of historic buildings and propose a decision-making model ranking the need of intervention in a historic building stock. In order to achieve this, it is essential to design a database system that enables the recording and indexing of the historic buildings pathology profile. Apart from pathology data, historic buildings are classified in terms of architecture style and type, historic importance and spatial data (position in the city). Monitoring building’s pathology profile has many positive impacts, such as knowing the building’s conservation status, the need for intervention, and the risk of collapsing. In a historic building stock, the safety assessment of buildings is a major research goal. It needs a rational and quantitative evaluation, which usually involves six steps:  information acquisition, data processing, numerical modeling, evaluation of potential scenarios, risk analysis, decision-making conservation plan.