To amend titles XIX and XXI of the Social Security Act to ensure that every child in the United States has access to affordable, quality health insurance coverage, and for other purposes.

Children's Health First Act - Amends title XXI (State Children's Health Insurance Program (SCHIP)) of the Social Security Act to grant states the option to expand coverage of children whose family income is any percentage up to 400% of the poverty-line. Authorizes states to offer purchase of coverage for uncovered children under SCHIP who are not otherwise eligible for assistance under...