Professional Boxing Amendments Act of 2013 - Amends the Professional Boxing Safety Act to: (1) authorize a tribal organization to establish a boxing commission; (2) prohibit arranging, promoting, or fighting in a match unless the match is approved by the United States Boxing Commission (USBC) and held in a state or on tribal land that regulates matches in accordance with USBC standards; (3) require specified pre-fight boxer physical examinations and to require the continuous presence during any match of an ambulance and emergency medical personnel; (4) provide for boxing registration with the appropriate boxing commission of an Indian tribe; (5) require a health and safety disclosure to a boxer when issuing an identification card and to establish procedures for review of a summary suspension; (6) require the USBC to develop guidelines for boxing contracting requirements and for rating professional boxers; (7) require the sanctioning organization for a match and its promoter to provide specified disclosures; (8) prohibit a promoter from arranging a championship match or a match scheduled unless all participating judges and referees are by the USBC; (9) require the USBC to establish and maintain a registry of comprehensive medical records and medical denials or suspensions for every licensed boxer; and (10) apply conflict-of-interest provisions to USBC officers and employees.

Establishes the USBC within the Department of Commerce to: (1) protect the health, safety, and general interests of boxers and to ensure integrity in professional boxing; (2) establish standards for, and issue, suspend, and revoke, boxing licenses; and (3) establish a national computerized registry of boxing personnel.