This paper presents the preliminary results of a research project aimed at exploring the perceived sense of presence incorporated in diverse technologies used in Virtual Museums. It initially presents the selection criteria and the five museum websites involved in the analysis. Then, it describes the evaluation process, in which a group of subjects explored the museums' on-line resources and completed a presence. The results of a double-phased statistical analysis are discussed, which investigated the technological conditions under which a Virtual Museum enhances the visitors' experience of presence.