In the midst of health care reform, eligible but uninsured children remain a cause for concern. Children in the same family often have differing eligibility status for public coverage. Mixed eligibility is associated with higher uninsurance rates, even when all children in a family are eligible. Medicaid policies play an important role in creating mixed-eligibility families via age-related eligibility thresholds and limited benefits for immigrants; states running separate Children's Health Insurance Program (CHIP) programs have higher uninsurance rates among eligible children. Recent policies to simplify enrollment have not lowered uninsurance among these children. States may improve take-up rates by focusing on eligible children in mixed-eligibility families.