: The heterogeneous and dynamic nature of components making up a web application, the lack of effective programming mechanisms for implementing basic software engineering principles in it, and undisciplined development processes induced by the high pressure of a very short time-to-market, make web application maintenance a challenging problem. A relevant issue consists of reusing the methodological and technological experience in the sector of traditional software maintenance, and exploring the opportunity of using reverse engineering to support effective web application maintenance. This paper presents reverse engineering approach that help to understand existing undocumented web applications to be maintained or evolved, through the extraction from domain ontology of conceptual schema describing a web application. The advantage of using ontology for conceptual data modelling is the reusability of domain knowledge. As a result of it the conceptual data model will be made faster, easier...