The Official Professional Baseball Rules Book governs all aspects of the game of Major League Baseball beyond what happens on the field of play. There are a number of sources for these rules, but they all ultimately are sanctioned by the Office of the Commissioner of Baseball. Examples of these rules are the Rule 5 draft (so-named for the applicable section of the rule book) and the injured list. Other examples include:

Rules Book

The Official Professional Baseball Rules Book is organized into the following sections:

Major League Rules

The below sections enumerate the numbered Major League Rules, both before and after Major League Baseball reorganized the minor leagues in advance of the 2021 season, as multiple rules were changed at that time. With the elimination of one-game playoffs in 2022, the tiebreaker rules were significantly modified, since all ties are now resolved by formula. The revised tiebreaker rules appear in the 2024 edition described below. As most rules do not state what the penalty is for a violation, broad discretion is granted to the Commissioner of Baseball via Rule 50, "Enforcement of Major League Rules", which specifies "action consistent with the commissioner’s powers under the Major League Constitution". The Major League Rules begin with a note stating that whenever a provision of any of its rules conflicts with a provision in the Basic Agreement (collective bargaining agreement) negotiated with the Major League Baseball Players Association, the provision in the Basic Agreement "shall in all respects control".

2019 edition

Source: The Rules are followed by an Acceptance; "The foregoing ... have been duly accepted by the Major League Clubs and the Leagues of the National Association." There are then Attachments to the Rules (numbers refer back to Rule # above):

2021 edition

Source: The Rules are followed by an Acceptance; "The foregoing ... have been duly accepted by the Major League Clubs." There are then Attachments to the Rules (numbers refer back to Rule # above):

2024 edition

Source: At the top of page 1, a bolded, fully capitalized statement indicates that where the rules conflict with the currently effective basic agreement with the Major League Baseball Players Association, the basic agreement controls. The rules are followed by an Acceptance stating, "The foregoing Major League Rules... have been duly accepted by the Major League Clubs." There are then numbered Attachments to the rules (numbers refer back to rule number above):