The objectives of this study are (1) to compare the prevalence of a medical home between children with public and private insurance across states, (2) to investigate the association between a medical home and state health care characteristics for children with public and private insurance. We performed a cross-sectional analysis of the 2007 National Survey of Children's Health, estimating the prevalence of parents' report of a medical home and its components for publicly- and privately-insured children in all 50 states and the District of Columbia. We then performed a series of random-effects multilevel logistic regression models to assess the associations between a medical home and insurance type, individual sociodemographic characteristics, and state level characteristics/policies. The prevalence of a medical home varied significantly across states for both publicly- and privately-insured children (ranges: 33-63 % and 57-76 %, respectively). Compared to privately-insured children, publicly-insured children had a lower prevalence of a medical home in all states (public-private difference: 5-34 %). Low prevalence of a medical home was driven primarily by less family-centered care. Variation across states and differences by insurance type were largely attributable to lower reports of a medical home among traditionally vulnerable groups of children, including racial/ethnic minorities and non-English primary language speakers. The prevalence of a medical home was not associated with state level characteristics/policies. There are significant disparities between states in parents' report of a medical home for their children, especially for publicly-insured children. Interventions seeking to address these disparities will need to target family-centered care for traditionally vulnerable populations of children.