Background: Over the past decade, the percentage of Americans with access to employer-sponsored insurance (ESI) has declined. Dependents, specifically children, are the most likely to bear the burden of lost coverage. Objectives: The objectives of this study were to 1) describe trends in children's health insurance taking into account the heterogeneity across different sub-populations and 2) assess the associations between individual, local (offers of ESI), and supply side (proximity to safety net hospitals) characteristics and children's health insurance. Methods: We analyzed locally collected survey data for children living in the 12 counties of greater Houston, Texas (years 2003, 2006, 2008, 2011). For each year, telephone interviews were conducted with caregivers through random digit dialing. Among households with at least one employed caregiver (N=2,508), we performed an adjusted multinomial logistic regression analysis to evaluate the odds of being publicly insured or uninsured, with the option for ESI and proximity to a public hospital as primary independent variables. Results: Low-income and racial/ethnic minority children experienced the largest increases in coverage through public insurance. Children in households without the option for ESI had higher odds (Odds ratio 10.87, 95% confidence interval 7.31-16.17) of being publicly insured or uninsured (Odds ratio 9.50, 95% confidence interval 6.14-14.70) compared to those in households with the option for ESI. Proximity to a public hospital was not associated with being uninsured. Conclusions: As the availability of ESI has declined, public insurance has acted as a safety net for low-income and minority children. While access to free care plays an important role, it may not substitute for insurance coverage.