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Medicare & Medicaid


Codified Medicare regulations are in 42 C.F.R. Parts 400–426, 475–505.

Codified Medicaid regulations are in 42 C.F.R. Parts 430–460.

The Code of Federal Regulations is available in many places, including FDSys.


Proposed & New Regulations

Proposed and new regulations are published in the Federal Register.

Browse recent regulations from the Centers for Medicare & Medicaid Services at

Note that a final rule published in the Federal Register explains the rule's background and purpose. See Medicaid Program; Disproportionate Share Hospital Payments-Treatment of Third Party Payers in Calculating Uncompensated Care Costs, 82 FR 16114 (Apr. 3, 2017).

Looking for the Background of a Regulation

The current CFR cites the Federal Register where a final regulation was published.

For example, 42 C.F.R. 442.2 cites:

[43 FR 45233, Sept. 29, 1978, as amended at 51 FR 24491, July 3, 1986; 53 FR 1993, Jan. 25, 1988; 54 FR 5358, Feb. 2, 1989; 56 FR 48865, Sept. 26, 1991; 59 FR 56235, Nov. 10, 1994]

HeinOnline [UW restricted] has the Federal Register back to 1935, so we can look up any of these, for instance, the 1994 amendment, 59 Fed. Reg. 56235—and its background, 59 Fed. Reg. 56116.

Use of Federal Register Preambles

Lawyers and courts use the preambles and comments in the Federal Register to interpret regulations are argue for or against the way the government is applying them. For instance:

snip from case

Harris v. Olszewski, 442 F.3d 456, 468 (6th Cir. 2012)