PurposeOne of the aims of library catalogs is to clearly represent the relationships existing between two or more bibliographic entities, enabling users to make sense of these relationships. Educational bibliographic relationships are the relationships between an educational work, such as a textbook, and its related works. The main interest of this study was to understand the nature of the supplementary work-to-work bibliographic relationships among educational works and the constitution of educational bibliographic families in the Canadian context using AMICUS (the Canadian national catalog). A thorough understanding of educational bibliographic relationships is required for understanding the Functional Requirements for Bibliographic Records (FRBR) supplementary relationships. Design/methodology/approachWe studied the extent and size of educational bibliographic relationships in the bibliographic universe found in the AMICUS catalog. This is an empirical investigation into the nature and extent of educational work-to-work bibliographic relationships by examining title of works, notes and added entries in bibliographic records. The study was carried out between September 1st 2010 and December 22nd 2010 and examines educational bibliographic relationships between Canadian 2009 publications in each class of the Dewey Decimal Classification (DDC). In other words, this study poses two main questions: What is the structure of educational supplementary bibliographic relationships in Canadian publications? Do significant differences exist across the ten DDC classes? FindingsResults show that 595 works of the 2009 bibliographic records in the AMICUS catalog contain an educational supplementary bibliographic relationship. Of the Canadian publications with an educational supplementary work-to-work bibliographic relationship that were studied, the rates of educational bibliographic relationships were relatively high in the fields of Science (27%), Technology (22%), Social Sciences (20%), and Language (19%). The results of this study suggest a set of guidelines for the establishment and maintenance of educational bibliographic relationships. Originality/valueThis is the first research to examine the educational bibliographic relationships, as supplementary relationships.