A scale for measuring the engagement properties of eHealth content was adapted from commercial advertising research. We define engagement as the process of involving users in health content in ways that motivate and lead to health behavior change. Complete responses were obtained from 230/260 participants exposed to health content from seven content areas in online remote testing. After viewing each of three randomly assigned health content areas, the participants completed two questionnaires. The first one assessed the appropriateness, applicability, motivation, and intentions to change or engage in health behaviors relevant to the set of content components displayed for that health topic. The second questionnaire was the eHealth Engagement Scale in which participants rated each of 12 descriptors on a 5-point Likert scale. Internal reliability of each of the two multi-item subscales of the Engagement Scale was .878 for Involving and .805 for Credible. A 4-factor solution eliminating three of the original 12 word descriptors was found to be the superior in the subsequent analysis of predictive validity. The eHealth Engagement Scale may prove to be an important mediator of user retention of information, intentions to change, and ultimately efforts to undertake and achieve behavior change.