Objective: To examine the use and impact of a dedicated health information Web site for adolescents. Method: Five hundred fifty-eight (27.2%) of all students in grades 7 through 12 from 4 schools logged onto the Web site; 1775 (86.4%) of all students in these grades completed a year-end health survey, with 455 (81.5%) of the students who used the Web site completing the survey. Dependent variables were help seeking and satisfaction ratings plus visits to specific Web site sections. Predictor variables were demographic characteristics, mental health, and psychosocial difficulties assessed at years' end. Results: Students logged on greater than 11,000 times during the year. Female students, students wanting professional help, those scoring higher on depressive vulnerability measures, and students reporting more severe mood problems were related to logging on frequently over longer periods of time, as well as viewing information sheets, posting and viewing questions and answers, and completing the symptom screen. Students accessing the Web site from 1 to 7 A.M. reported higher levels of distress than did students who accessed the Web site at other times of the day. Visits to the Web site were positively associated with visits to school health centers and guidance counselors and referrals to a health professional. Conclusions: Results are consistent with a health-needs model of utilization of this Internet-based health resource. A school-based health information Web site holds significant promise for health promotion and early self-identification for emotional problems. (Contains 3 tables and 3 figures.)