We used a retrospective, matching, birth cohort design to evaluate a comprehensive, coalition-led childhood immunization program of outreach, education, and reminders in a Latino, urban community. After we controlled for Latino ethnicity and Medicaid, we found that children enrolled in the program were 53% more likely to be up-to-date (adjusted odds ratio = 1.53; 95% confidence interval = 1.33, 1.75) and to receive timely immunizations than were children in the control group (t = 3.91). The coalition-led, community-based immunization program was effective in improving on-time childhood immunization coverage.