The presence research community would benefit from a reliable and valid cross-media presence measure that allows results from different laboratories to be compared and a more comprehensive knowledge base to be developed. The ITC-Sense of Presence Inventory (ITC-SOPI) is a new state questionnaire measure whose development has been informed by previous research on the determinants of presence and current self-report measures. It focuses on users' experiences of media, with no reference to objective system parameters. More than 600 people completed the ITC-SOPI following an experience with one of a range of noninteractive and interactive media. Exploratory analysis (principal axis factoring) revealed four factors: Sense of Physical Space, Engagement, Ecological Validity, and Negative Effects. Relations between the factors and the consistency of the factor structure with others reported in the literature are discussed. Preliminary analyses described here demonstrate that the ITC-SOPI is reliable and valid, but more rigorous testing of its psychometric properties and applicability to interactive virtual environments is required. Subject to satisfactory confirmatory analyses, the ITC-SOPI will offer researchers using a range of media systems a tool with which to measure four facets of a media experience that are putatively related to presence.