A review of published controlled trials was conducted to evaluate components, utility, and efficacy of Web-based healthcare interventions. Nine studies met the established review criteria. Knowledge gains were the most commonly reported significant changes; rarely were there measures or significant changes on behavioral outcomes. Studies varied in format of personal contact with participants, in the structure or sequence of intervention content, and in design features. Dosage was inconsistently measured and process evaluation was relatively absent. Despite limitations, several studies reported significant effects. Based on best evidence-to-date, elements of technologically mediated interventions important to future research are summarized. Taken together, research suggests that Web-based interventions may be an efficacious delivery system, especially for those with chronic conditions amenable to self-management and to those with various limitations to accessing healthcare.