Information technology (IT) is fundamentally altering the way in which healthcare is delivered to consumers, and offers the promise of improving patient safety, reducing medical errors, improving efficiency, and increasing the reach of health delivery programs. The aim of this research is to examine the factors affecting the adoption and post-adoption of a significant IT innovation in healthcare: online health intervention programs that provide technology-mediated guidance and aid individuals in self-managing their health care. A key challenge confronting health program providers is that of motivating initial enrollment and subsequent continued participation in these interventions. Limited prior work in the information systems and health informatics literature has examined the uptake of technology-mediated health intervention programs. Using data from an online healthcare portal site, this study proposes and empirically tests relationships between the determinants and participation in online health intervention programs.