Researching the Code of Massachusetts Regulations

The Code of Massachusetts Regulations ("CMR") contains a complete set of regulations promulgated by Massachusetts state agencies.

Table of Contents

Introduction to the CMR

What is the CMR?

CMR Image

The CMR is the administrative law of executive branch state agencies, compiled into a multi-volume set. It is updated every two weeks by filings published in the Massachusetts Register.

Prior to 1976, there was no centralized way in which agencies published their regulations; however, in 1976 this changed with the first edition of the CMR. A second edition of the CMR was released in 1978, and the current third edition was released in 1987; this edition continues to be updated to this day.

The Massachusetts Trial Court Law Libraries maintain an unofficial online version of the CMR arranged by number or subject. The Social Law Library digitized the CMR from 1987 to the present, and hosts it on LLMC Digital. Official copies can be found in paper in the State Library’s Main Reading Room, and individual print regulations can be purchased from the Secretary of the Commonwealth's Massachusetts State Bookstore.

How is the CMR organized? What does a citation look like?

The CMR is first organized by the “title number” that is assigned to each agency, then by regulation chapter number, and then by section number.  

For example: 204 CMR 4.04

204: Is the title number assigned to the Alcoholic Beverages Control Commission.

4.00: Is the regulation chapter number, which is titled “Prohibition of Certain Practices.”

4.04: Is the section number under the chapter, which is titled “Exceptions.”

What is the difference between a permanent and an emergency regulation? How are regulations passed?

The Regulations Manual, published by the Secretary of the Commonwealth, is an in-depth guide to regulations and the regulatory process in Massachusetts. It will answer all of your questions.

Additional Resources

Important Resources for Research

The Massachusetts Register

Massachusetts Register Cover Image

The Massachusetts Register is published every two weeks by the Secretary of the Commonwealth. It contains the new regulation filings that are used to update the CMR, as well as regulatory hearing notices and other documents.

Each issue of the Massachusetts Register is numbered on the top right hand side of the cover, and these numbers are cited in the Cumulative Tables.

State Library print holdings: 1976 to date

Available online in the State Library's digital repository



The Cumulative Tables

Massachusetts Register Cumulative Tables Image
An example from the Massachusetts Register Cumulative Tables

A Cumulative Table, which is published in every issue of the Massachusetts Register, documents all of the changes to the CMR, starting at the beginning of the calendar year up through the most current Register issue.

The Tables are a helpful tool to have when tracing the history of a regulation, but keep in mind that the information they provide is not specific, and reviewing filings in the Registers will be necessary.


The Tables contain: 

  • Title number and chapter number citations (e.g. 101 CMR 204.00) 

Note: The Tables rarely provide section number-level information (e.g. 101 CMR 204.16)

  • The names of the agencies and the chapter headings
  • The issue # of the Massachusetts Register in which the filings were published
  • The effective date of the regulation

If you don’t see your regulation’s citation during a calendar year, it means there were no amendments that year.

It’s also important to keep in mind that regulations can move to a different location in the CMR; this most often occurs when there are large-scale changes made to an agency, such as reorganization.

The final year-end Cumulative Tables from 1976 to date have been digitized and can be found in the State Library’s digital repository.

Additional Resources

Pre-Codified Regulations

The State Library has binders containing regulations that were issued prior to the creation of the CMR. These are in paper format only and are organized by agency name. Researchers may visit the State Library on-site to review these filings and receive assistance from the State Library Reference Department.

Note: Prior to the building code’s statewide codification in 1976 as 780 CMR, cities and towns in Massachusetts each enforced their own building code. If you have a particular city or town in mind, check with local government offices and public libraries to see what they have on file. Unofficial current and past editions of the statewide building code (780 CMR) can be viewed on

Starting Your Regulatory Research

I want to know what a regulation looked like during a specific year. How do I do that?

The easiest way is to look at a copy of the CMR as it appeared during that particular year. The Social Law Library has a large collection of CMRs that were microfilmed at the end of each calendar year for the years 1978-1980 and 1987-2016. Keep in mind that you may need to trace the regulation back a little if you want to see how it appeared prior to the end of the year. 

How do I trace the history of a regulation back to a certain point?

  • First, take a look at the pages of your regulation in the most current official paper edition of the CMR. Each page has the date on which it was last amended.
  • Starting from the latest amendment year, work your way backward through the Cumulative Tables and make note of the Massachusetts Register # cited on the right hand side of the Table whenever your regulation appears.

Note: Remember, the Tables generally provide information at the chapter level only. 

  • Once you’ve worked your way as far back as desired, begin reviewing the filings in the Massachusetts Registers to see which filings pertain to the section of the regulation you are researching.

How do I trace the entire history of a regulation?

You can continue to move backwards, as shown in the previous section of this guide; however, if you know you want to review a regulation’s entire history, it’s best to start at the beginning and move forward.

  • First, start at the first Cumulative Table (1976) and move forward through the years until you find when your regulation first appears.

Note: Keep in mind that your regulation may have existed under a different citation earlier on. To check this, try searching the Tables using CTRL+F for keywords that would be found in your regulation’s title/heading.

  • Once you think you’ve found when your regulation was first added, work forward through the Tables for each year and note down the Massachusetts Register # cited on the right hand side of the Table whenever your regulation appears.

Note: Remember, the Tables generally provide information at the chapter level only. 

  • Once you’ve worked your way forward through the most current Table, begin reviewing the filings in the Massachusetts Registers to see which filings pertain to the section of the regulation you are researching.
  • You may also want to review pre-codified regulations (regulations that were issued by agencies prior to the CMR). These are currently in paper format in the Library, and our reference staff can assist you with finding what you need.  

Why was the regulation that I’m researching created/amended/repealed?

Some suggestions on where you might find information on the intent of a change that has occurred:

  • Filing cover sheets: Each filing that is published in the Massachusetts Register has a cover sheet that includes brief information, such as important dates, the regulatory authority (MGL), fiscal effect, and a statement of the action taken by the filing on existing provisions of the CMR.
  • Agency publications: Such as bulletins, notices of public hearings, annual reports, newsletters, meeting minutes, etc. Some of these publications can be found in the Massachusetts Registers, but researchers will also want to look on the agency’s website, in the Library’s online catalog, and in the State Library's digital repository.  
  • Public hearing and drafting materials: Current hearing materials, such as testimony and handouts, and draft versions of the regulation may be found on the agency’s website. Researchers will need to contact the agency directly for earlier materials.
  • Agency contact person: Each filing cover sheet lists the agency’s contact person for questions and requests. Take a look at the filing cover sheets in the latest Massachusetts Registers for the most current contact person for the agency/regulation you are researching.
  • General Laws of Massachusetts (M.G.L.): Each regulation cites an M.G.L. chapter (and sometimes section) as its regulatory authority (e.g. 101 CMR 423.00: M.G.L. c. 118E). Check to see if there were any changes to the law around the time that the regulation that you are researching was also changed. You might find yourself doing some legislative research! Annotated versions of the MGL can be found in the Library’s Reading Room.

Additional Resources

Contact   for Researching the Code of Massachusetts Regulations


Open M-F 9 a.m.–5 p.m.

Open M-F 9 a.m.–5 p.m. *Advance appointments are strongly recommended


(617) 727-9730


Main Library
Massachusetts State House, 24 Beacon Street, Room 341, Boston, MA 02133
Special Collections Department
Massachusetts State House, 24 Beacon Street, Room 55, Boston, MA 02133

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