Medicaid and CHIP Safety Net Preservation Act of 2004

Medicaid and CHIP Safety Net Preservation Act of 2004 - Amends title XIX (Medicaid) of the Social Security Act (SSA) with respect to Section 1115 (which gives the Secretary of Health and Human Services broad authority to conduct research and demonstration projects under several programs, including Medicaid and SCHIP (State Children's Health Insurance) under SSA title XXI, and to waive certain statutory requirements for conducting these projects without congressional review).

Prohibits the Secretary from imposing or approving under Section 1115 authority: (1) a cap, limitation, or other restriction on payment to a State for amounts expended as medical assistance in accordance with the Medicaid program; (2) an elimination of, or modification limiting, the entitlement of an individual to receive any medical assistance for which Federal financial participation is claimed under Medicaid; (3) an elimination or modification of the amount, duration, or scope of early and periodic screening, diagnostic, and treatment services; or (4) an elimination or modification of the amount, duration, or scope of certain safety-net services, including those of a rural health clinic and a federally-qualified health center.

Amends SSA title XXI to prohibit the Secretary from approving a waiver, experimental, pilot, or demonstration project (or project modification) that would allow the use of SCHIP funds to provide child health assistance or other health benefits coverage to a nonpregnant childless adult.

Amends SSA title XI to establish public notice and comment requirements for States and the Secretary with respect to any State proposal for an experimental, pilot, or demonstration project (or project modification) to assist in promoting Medicaid or SCHIP objectives that would result in a substantive change in eligibility, enrollment, benefits, financing, or cost-sharing under a State program.