ABSTRACT:A 15-site health maintenance organization (HMO) implemented a mass influenza vaccination program to heighten awareness of the vaccine and immunize more “at-risk” members. Successful interventions conducted over a two-year period included: a direct mail leaflet, pharmacy bag reminders, posters at each medical center, articles in the HMO member newsletter, staff education, standing orders for nursing and, most important, the availability and access to vaccination through walk-in clinics. Immunization rates were examined for patients considered “at risk.” In addition, assessments were made to determine program effectiveness and patient and staff satisfaction.