The modern health care system is being irrevocably changed by the development and introduction of new health information technologies (such as health information systems, decision-support tools, specialized websites, and innovative communication devices). While many of these new technologies hold the promise of revolutionizing the modern health system and facilitating improvements in health care delivery, health education, and health promotion, it is imperative to carefully examine and assess the effectiveness of these technological tools to determine which products are most useful to apply in specific contexts, as well as to learn how to best utilize these products and processes. Without good evaluative information about new technologies, we are unlikely to reap the greatest benefits from these powerful new tools. This chapter examines the demand for evaluating health information technologies and suggests several strategies for conducting rigorous and relevant evaluation research.