Objective: To ascertain the cost-effectiveness and the benefit-cost ratios of a community-based hepatitis B vaccination catch-up project for Asian American children conducted in Philadelphia, Pa, from October 1, 1994, to February 11, 1996., Design: Program evaluation., Setting: South and southwest districts of Philadelphia., Participants: A total of 4384 Asian American children., Interventions: Staff in the community-based organizations (1) educated parents about the hepatitis B vaccination, (2) enrolled physicians in the Vaccines for Children program, and (3) visited homes of children due for a vaccine dose. Staff in the Philadelphia Department of Public Health developed a computerized database; sent reminder letters for children due for a vaccine dose; and offered vaccinations in public clinics, health fairs, and homes., Main Outcome Measures: The numbers of children having received 1, 2, or 3 doses of vaccine before and after the interventions; costs incurred by the Philadelphia Department of Public Health and the community-based organizations for design, education, and outreach activities; the cost of the vaccination; cost-effectiveness ratios for intermediate outcomes (ie, per child, per dose, per immunoequivalent patient, and per completed series); discounted cost per discounted year of life saved; and the benefit-cost ratio of the project., Results: For the completed series of 3 doses, coverage increased by 12 percentage points at a total cost of $268 660 for design, education, outreach, and vaccination. Costs per child, per dose, and per completed series were $64, $119, and $537, respectively. The discounted cost per discounted year of life saved was $11 525, and 106 years of life were saved through this intervention. The benefit-cost ratio was 4.44:1., Conclusion: Although the increase in coverage was modest, the intervention proved cost-effective and cost-beneficial.