This study evaluates the Hope For A Million Kids Immunization Event in East Harlem, New York, in 1996. The methodology: (1) Documented planning and implementation processes. (2) Analyzed numbers of children reached through the outreach initiative and those actually immunized due to the Event. (3) Assessed associated costs. The Event reached and educated 120,000 children through door-to-door canvassing. Substantially fewer children, 562, registered at the Health and Human Services Fair, and 211 children were immunized at a cost of about $594 per immunized child. Immunization registries may be more effective in increasing childhood immunization rates.