Background: The goal year for the Healthy People 2010 initiative is approaching. Purpose: This article aims to assess progress toward reaching the overarching goal of eliminating disparities in vaccination coverage among young children in the U.S. Methods: Coverage for the 4:3.1.3-3:1 vaccine series (at least four doses of diphtheria-tetanus-pertussis, three poliovirus, one measles-mumps-rubella, three hepatitis B, three Haemophilus influenzae type B, and one varicella vaccine) was assessed among 185,516 children in the 2000-2008 National Immunization Surveys. Observed and adjusted disparities in coverage were evaluated for various sociodemographic groups previously associated with vaccination coverage. Linear trends ill disparities were assessed. Results: In 2000, disparities among population segments were significant (p<0.05) for all sociodemographic factors assessed except provider participation in the Vaccines for Children program. By 2008, most disparities were smaller than those in 2000, and racial and urban/suburban/rural differences were reduced to levels below significance. Disparities between children living in suburban versus rural localities narrowed approximately 0.5% per year. Vaccination covet-age increased substantially among children in all sociodemographic groups, although children without siblings were the only group to reach the 8096 tat-get by 2008 Conclusions: Progress has been made toward eliminating vaccination coverage disparities among children in various sociodemographic groups in the U.S. As the end of the Healthy People 2010 goal period approaches, maintaining and advancing these reductions will require innovative strategies to reach Underserved groups. (Am J Prev Med 2010,38(2).127-137) Published by Elsevier Inc on behalf of American Journal of Preventive Medicine