Monday, September 8, 2025

Understanding the Code of Massachusetts Regulations (CMR)

In 2013, the State Library published a blog post about the Code of Massachusetts Regulations (CMR), the official compilation of rules created by Massachusetts state agencies. Since then, access to the CMR has expanded, and the Library has continued to grow its collections, both in print and online. This updated post revisits the topic to provide current information about the CMR and the many ways researchers can explore these resources at the State Library and beyond. 

As we mentioned, the CMR contains the official rules that Massachusetts state agencies create and use to carry out state laws. These regulations cover a wide range of topics, from food safety standards to professional licensing requirements, and are published to ensure transparency and public access to the procedures and policies that affect daily life in the Commonwealth.

The CMR as we know it began in 1976. Prior to that there was no centralized way in which agencies published their regulations. A second edition of the CMR was released in 1978, and the third and current edition was released in 1987. This edition continues to be updated to this day.

How Regulations Are Published

Regulations are filed with the State Publications and Regulations Division of the Office of the Secretary of the Commonwealth and published biweekly in the Massachusetts Register. Each issue of the Register includes:
  • Notices of proposed regulations and public hearings
  • New, amended, and emergency regulations
  • Executive Orders and Attorney General Opinions
  • Cumulative Tables showing changes since the last codification

What the Numbers Mean

Each regulation is assigned a three-part citation. For example, 105 CMR 125.004:
  • Title number (e.g., 105 CMR) designates the agency
  • Chapter number (e.g., 105 CMR 125) indicates a subject area
  • Section number (e.g., 105 CMR 125.004) pinpoints specific provisions
The first digit of the title number typically corresponds to the Executive Office, while the remaining digits identify the agency itself.


Accessing the CMR at the State Library

The State Library of Massachusetts is a valuable resource for anyone researching Massachusetts regulations. Here's how we can help:
  • CMR in Print 
    • We maintain a current Reading Room copy of the CMR for quick reference, updated as new regulations are filed.
  • Historical Collection and Stacks Copy 
    • Our Stacks copy of the CMR includes older versions with the Massachusetts Registers still intact, which is useful for identifying regulatory changes over time.
  • Massachusetts Register 
    • We have the Massachusetts Register in print, and many issues are available in our digital repository.
  • Cumulative Tables 
    • We house a comprehensive collection of the Cumulative Tables starting in 1976 to present. The tables list updates made to the CMR and allow researchers to trace when changes were made to specific chapters and sections.
  • Pre-Codified Regulations 
    • For older regulations issued before the formal CMR codification system began in 1976, we provide access to the pre-codified edition in print at the library, as well as in our digital repository. The pre-codified edition consists of 12 boxes, each containing several folders. The boxes are organized by agency, similar to the way the CMR now contains title numbers. Read on for information about accessing the pre-codified CMR digitally.

Online Access to the CMR

If you can’t visit the Library in person, the following resources provide online access to current and historical regulations:
Whether you’re a legal researcher, student, public policy professional, or just curious about how state government works, the State Library is here to support your research into Massachusetts regulations. Visit us in Room 341 of the Massachusetts State House or contact our reference librarians for assistance at reference.department@mass.gov.


Jessica Shrey
Legal Research Reference Librarian

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