The Internet is a potentially powerful source of low- or no-cost programs through which individuals can be guided in changing their behavior to improve health. Using the Transtheoretical Model and survey methodology, the authors sought to produce reliable and valid instruments for assessing "stage of change" and "informed decision making," and to generate cross-sectional and longitudinal stage-of-change data for a sample of Internet users, as they apply to Internet use for health promotion and disease management. They found that only 24.7% of their sample used the Internet for these purposes and concluded that considerably more research will be needed to determine how to help significant percentages of populations to progress toward enhancing their health through the Internet.