Cooperative collection planning is critical to the future of zoological parks and aquariums, yet few published models currently exist for collection plan development and implementation. In particular, there has been little discussion about the relationship between regional and institutional collection planning or about what defines a quality regional collection plan (RCP). This article documents the regional collection planning process adopted by the AZA Marsupial and Monotreme Taxon Advisory Group (TAG). More specifically, it outlines the philosophical foundation of the North American RCP for Marsupials and Monotremes, the organizational structure developed by the TAG to facilitate communication, evaluation and institutional participation, and other important details of the planning process. It also documents how the RCP was used by one institution (Los Angeles Zoo) to formulate its Institutional Collection Plan (ICP). Zoo Biol 17:433–451, 1998. © 1998 Wiley-Liss, Inc.