Computer-generated reminders for patients and physicians can increase provision of preventive services. On July 1, 1989, the Department of Family Medicine at the Medical University of South Carolina extended a computerized prevention reminder system to all physicians and adult patients in the department's clinical practice. The prevention program consisted of computer-generated physician reminders for any deficiencies in five preventive services at the time of patient visits, a personalized patient reminder letter sent just before a patient's birthday, and educational interventions. We defined adherence using a population-based approach, that is, the percentage of all eligible patients who had received the preventive services within the recommended period of time. The data revealed that the percentage of patients who received preventive services either increased or remained stable during the 12-month study period, which ended July 1, 1990. Adherence was greater for women, for older patients, and for those with Medicare/Medicaid and HMO insurance. We noted higher rates of adherence for all five preventive services, compared with baseline rates of adherence recorded on July 1, 1988. A population-based approach to prevention allows physicians to become more active in providing preventive care to patients. Computer-based reminder and tracking systems can integrate population-based prevention into practice.