Visit rates, emergency care use, and markers of quality of care were compared between adolescents who use school-based health centres and those who use other community centres within a safety-net health care system for low-income and uninsured patients. Data were collated from Denver Health electronic medical charts, the Denver Health immunization registry, and Denver Public Schools enrolment data for the period from August 1, 2002, to July 31, 2003. The cohort comprised all 14- to 17-year-old Denver Public Schools high school enrolees who were active Denver Health patients and were either uninsured or insured by Medicaid or the State Children’s Health Insurance Program. School-based health centre users (n=790) were less likely than other users (n=925) to be insured (37% vs 73%), but were more likely to have made ≥3 primary care visits (52% vs 34%), less likely to have used emergency care (17% vs 34%), and more likely to have received a health maintenance visit (47% vs 33%), an influenza vaccine (45% vs 18%), a tetanus booster (33% vs 21%), and a hepatitis B vaccine (46% vs 20%). The authors conclude that school-based health centres augment access to health care for underserved adolescents compared with traditional outpatient care sites.