The Maurice Lamontagne Institute, which is located in Mont-Joli (Québec, Canada), houses a collection of marine organisms originating mainly from the Estuary and Gulf of St. Lawrence, but also from the Canadian Arctic. The collection includes specimens of more than 1460 species that were collected between 1900 and 2014, and these provide taxonomic and biogeographic reference material for to the scientific community, and educational information to the general public. This article summarizes the history, diversity and geographic distribution of the specimens, which have proven important for the work of the Department of Fisheries and Oceans and its affiliates.