Objectives. We compared levels of untreated dental caries in children enrolled in public insurance programs with those in nonenrolled children to determine the impact of public dental insurance and the type of plan (Medicaid vs State Children’s Health Insurance Program [SCHIP]) on untreated dental caries in children., Methods. Dental health outcomes were obtained through a calibrated oral screening of kindergarten children (enrolled in the 2000–2001 school year). We obtained eligibility and claims data for children enrolled in Medicaid and SCHIP who were eligible for dental services during 1999 to 2000. We developed logistic regression models to compare children’s likelihood and extent of untreated dental caries according to enrollment., Results. Children enrolled in Medicaid or SCHIP were 1.7 times (95% confidence interval [CI] = 1.65, 1.77) more likely to have untreated dental caries than were nonenrolled children. SCHIP-enrolled children were significantly less likely to have untreated dental caries than were Medicaid-enrolled children (odds ratio [OR]=0.74; 95% CI=0.67, 0.82). According to a 2-part regression model, children enrolled in Medicaid or SCHIP have 17% more untreated dental caries than do nonenrolled children, whereas those in SCHIP had 16% fewer untreated dental caries than did those in Medicaid., Conclusions. Untreated tooth decay continues to be a significant problem for children with public insurance coverage. Children who participated in a separate SCHIP program had fewer untreated dental caries than did children enrolled in Medicaid.