A consensus among biologists has been growing in recent years for the development of a global list of accepted species (and other taxa). To date, much discussion has focused on visions for how such a list would benefit many scientific and societal disciplines. Less emphasis has been placed on understanding the many technical challenges of compiling and maintaining such a list. Challenges include details of implementation such as defining what each entry on the list represents, the scope (taxonomic breadth), granularity (only species, all taxonomic ranks, unnamed operational taxonomic units), and level of confidence in the status of individual list entries. The specific properties and minimum information requirements of list items need to be defined, and a process for ensuring accuracy, consistency, and noting uncertainties, needs to be adopted. Perhaps the greatest technical challenge is in developing the procedures by which the global list is created, updated, and maintained. Considerations of how to incorporate obscure and newly described taxa, the extent and specific implementation of a review process, and mechanisms for arbitrating disputes or alternative taxonomic viewpoints will need to be addressed through an open and transparent process with broad engagement from multiple communities. Details concerning how the global list can be accessed, how it will be maintained, and the way in which the list and its contents are properly cited need to be determined. Many of these issues have been considered and sometimes solved by the Catalogue of Life, which should serve as the core foundation for the actual implementation of any global list of species.