Oral caries is the most prevalent chronic disease among US children, and disproportionately impacts those of low socioeconomic status. Studies have shown that the Special Supplemental Nutrition Program for Women Infants and Children (WIC) improves access to dental care among Medicaid children. This study investigated the impact of WIC, Medicaid, and the State Children's Health Insurance Program (SCHIP) on the prevalence of dental caries among low-income children. The 1999-2000 and 2001-2002 NHANES data were utilized for this analysis. Children 2-4 years old who participated in WIC, Medicaid, or SCHIP, or who were uninsured, and for whom both interview and complete oral health exam data were available (n = 597) were included in the study. Multivariate logistic regression modeling was conducted to examine the effects of program participation on caries. There was no statistically significant association between dental caries and participation in public assistance programs. The risk of dental caries for children in MedicaidSCHIP only was comparable to the risk for children in WIC and MedicaidSCHIP (OR = 1.04; 95%CI = 0.622, 1.745) and also to uninsured children (OR = 0.96; 95%CI = 0.523, 1.773). Dental caries were not impacted if the child did not have a preventive dental visit in the past 6 months (OR = 0.68; 95% CI = 0.436, 1.063) or did not have a regular dental care provider (OR = 1.15; 95% CI = 0.646, 2.044). Participation in WIC and MedicaidSCHIP does not improve the oral health of low-income children. Because this population is a high-risk group requiring more specialized efforts, improving access to care is not sufficient to improve oral health. In addition to increased utilization of services, the program partnership between WIC and MedicaidSCHIP must provide targeted, educational interventions to prevent dental caries. It may also be necessary to increase the recommended number of preventive visits for low-income children.